The 2024 Levels Guide to Metabolic Health Interventions

Cut sugar? Cold plunge? Zone 2? You can do plenty of things to improve your health, but where to start? Here’s our subjective mega-guide to some of the most common interventions for people at all stages of their health journey

Written By

The Levels Team

Reviewed By

Dr. Ami Kapadia

Updated: 11/21/2024

Published: 11/21/2024

25 mins read

If you spend any time consuming health news or social media, you’re inundated with advice on what you must do to achieve optimal health. The truth is, plenty of those activities may be good for you and may make you healthier. But that doesn’t mean they’re the best way for you to spend your time and energy right now. Depending on where you are in your journey, some behaviors will give you more bang for your buck than others.

In this guide, we look at many of the most common behavior interventions suggested for optimal metabolic health and group them into four tiers, roughly tied to where someone might be in their willingness or ability to make changes to improve their health:

The Essentialist
The Explorer
The Enthusiast
The Expert

We’ve given each intervention a 1-5 ranking (5 is best [easiest, most effective, best evidence]; 1 is worst) across four vectors: affordability, accessibility, effectiveness, and evidence. We know these rankings are highly subjective and will differ among people. What feels easy or cheap for you may be daunting for me. Experts can disagree in good faith about the quality of evidence. And what’s effective for my goals may not be for yours. With those caveats, here’s how we thought about the 1-5 scale for each.

Affordability = How simple or affordable is this intervention as a one-time or ongoing expense?

1 = Costs more than $500+ or $100+/month (e.g., getting a full-body MRI)
2 = Costs $250+ or $50+/month (e.g., taking supplements)
3 = Costs $100+ or some small recurring expense (e.g., buying a weight set)
4 = Costs $20 or less, no recurring expense (e.g., eating more fiber).
5 = Is free or nearly cost-neutral (e.g., buying an apple instead of a candy bar).

Accessibility = Does the activity require a significant effort or a meaningful lifestyle change?

1 = Requires a lifestyle change or something that would be difficult for most people (e.g., daily cold plunging)
2 = Requires several hours or significant physical exertion (e.g., doing regular HIIT workouts)
3 = Requires a few hours or more a week or regular, consistent effort (e.g., doing Zone 2 exercise a few times a week, sticking to a weight loss strategy)
4 = Requires some effort but can be adopted as a habit by most people (e.g., increasing daily fiber intake, going for a 20-minute walk after dinner).
5 = Requires minimal effort or is simple to work into a busy routine (e.g., doing five minutes of deep breathing exercises).

Effectiveness = How noticeable a difference will this make in your metabolic health? How quickly or effectively will the intervention deliver noticeable improvements in quality of life or critical markers?

1 = Effective around the margins for those already doing everything else (e.g., cold plunging, advanced testing)
2 = May be good for you, and effects might not be apparent (e.g., carb cycling, rigorously avoiding seed oils)
3 = Likely to improve health, but more of an optimization (e.g., improving gut health, meditation)
4 = Very likely to improve health for most people (e.g., eating more protein, wearing a CGM at least once)
5 = Core activities that will definitely improve health (e.g., walking, reducing added sugar)

Evidence = How well does research support the effectiveness of this intervention? Are there a lot of extensive studies? Is there good-faith disagreement among experts?

1 = Very little to no human research showing significant effects, or significant legitimate controversy
2 = Some small-scale human studies or multiple animal or cellular studies
3 = Mixed evidence in the studies, but some evidence of effectiveness in humans
4 = Meaningful meta-analyses or reviews; some credible conflicting evidence
5 = Overwhelming evidence that this is effective; multiple large-scale studies or meta-analyses finding effectiveness; little controversy among credible experts

Under each item, we’ve also added some useful studies on the topic if you want to get a taste of the research yourself.

Consider this list a ladder of behavior change: Once you’ve consistently nailed The Essentialist Level, add activities from the next tier. Remember, the goal is not for everyone to become an Expert. Simply performing the core behaviors at the bottom of the ladder will significantly impact your health and longevity, especially if you’ve not regularly done them before. And if something higher up the ladder entices you or feels suitable for what you’re trying to solve, give it a shot.

The most important thing is that you feel empowered to take charge of your health and know that no matter where you are on your journey, you can make meaningful changes to your health.

Level 1: The Essentialist

If you’re the kind of person who has traditionally not paid much attention to your health but has recently had a spouse, friend, or doctor suggest you start, this is the tier for you. You’re not looking to optimize or invest a lot of time or money into new gadgets or fads; you just want simple, proven things you can do that will produce results.

Think of these as the core behaviors all of us—from proud couch potatoes to professional athletes—must consistently do. These simple activities will produce actual results and are the base for any healthy lifestyle.

Expected outcomes:

Improved mood and energy
Reduced risk of chronic conditions like diabetes or fatty liver

🥦 Choose whole foods and minimize added sugar

Effectiveness: 5️⃣

Diet is the biggest driver of metabolic health and the most likely cause of high glucose variability. Carbs are in almost everything we eat, and the standard American diet is full of refined carbs, processed food, and added sugar. If you aren’t mindful of what you take in, you are likely living in a near-constant state of glucose (blood sugar) spikes or crashes. Opting for whole foods is the easiest way to eliminate added sugars, but when you eat packaged foods, just glance at the label and try to avoid anything with added sugars or opt for the lowest amount possible.

Work up to reducing foods with refined flours.

Eating this way is also highly likely to leave you feeling better. Blood sugar spikes and crashes have near-term physiological effects (fatigue, brain fog); avoiding this variability will likely give you more sustained energy.

Evidence: 5️⃣

Science has established that carbs turn into glucose when you eat. Excess glucose raises your blood sugar, which causes excess insulin to be released. High insulin over time can lead to insulin resistance and Type 2 diabetes. In general, few would argue in favor of more added sugar instead of less. And while there is debate about exactly how bad processed food is, there is little debate that whole foods are good for you.

We know less about precisely what glucose levels are normal and healthy for a general population and why some people become insulin resistant (or progress from prediabetes to diabetes) while others don’t.

Research Primer:

Affordability: 4️⃣

Processed and fast food is cheap, especially compared to organic or grass-fed whole foods. But you don’t need to go full Whole Foods to improve what you’re eating. Here are a few ways to eat healthier while remaining cost-conscious:

Swap expensive soda for free water.
Opt for frozen or canned vegetables, or buy what’s on sale.
Remove processed snacks from your house and replace them with whole alternatives, such as fruit, or minimally processed foods, like cheese.
Retailers like Costco and Sam’s Club sell whole foods like nuts and veggies, so you can save by buying in bulk.

Accessibility: 4️⃣

If you’re eating a highly processed diet, finding whole-food swaps and checking labels to eliminate added sugar will take some effort. Many areas of the country lack access to fresh, whole foods, and sugar hides under many names. Finally, ultra-processed foods are engineered to be tasty and addictive. But the work here is front-loaded: once you make the necessary changes, you just have to stick to them.

Read more:

🚶 Move every day, especially after meals

Effectiveness: 5️⃣

Moving after meals is one of the best ways to blunt the glucose response to any meal. Physical activity can’t entirely erase a candy bar or bowl of Lucky Charms, but it can reduce the magnitude of the spike.

Daily exercise is also vital to all manner of disease prevention, from obesity to cardiovascular risk to cancer. Physical activity improves short- and long-term mental health and reduces stress. While vigorous exercise several times a week is best, any exercise is better than none. If you’re not in the habit of walking every day, doing so can enormously affect your health.

Work up to aiming for 10,000 steps daily, or about five miles. This number is somewhat arbitrary, but studies have found that it will produce tangible results and that even short of that goal, there is a relationship between higher steps and better health.

Evidence: 5️⃣

Several studies show that even light walking after a meal lowers glucose response and that moderate exercise over time improves overall insulin sensitivity and helps prevent weight gain.

Additionally, hundreds of studies show the benefits of exercise over a sedentary lifestyle for every aspect of health.

The open questions around exercise are only at the fringes of performance, with incremental differences, such as the benefits of exercising fasted versus fed or at a particular time of day.

Research Primer:

The relationships between step count and all-cause mortality and cardiovascular events: A dose–response meta-analysis

Affordability: 5️⃣

It’s easy to get intimidated by the cost of gym memberships or fancy machines. But you don’t need to spend a dime to get all the exercise you need. You can walk (or do squats or pushups) in any outfit just about anywhere. You can find hundreds of free bodyweight workouts online and on YouTube. You can lift heavy things around your house or yard.

Accessibility: 5️⃣

If you don’t exercise at all, working more movement into your day will require some thought, but there are so many simple ways to do it:

Get your heart rate up by dancing, cleaning, or playing with your dogs.
If you work at a desk, get up at least once an hour and do 10 squats
Walk around while on phone calls, even if it’s just pacing around your cube or house.

🛌 Aim for 7-8 hours of sleep a night

Effectiveness: 5️⃣

Sleep is essential for overall health and well-being. Adequate sleep helps the body repair and rejuvenate itself, improving physical and mental health. Lack of sleep can have adverse effects on memory, concentration, and mood, and it can increase the risk of obesity, diabetes, and heart disease. Sleep also plays a crucial role in regulating hormones, such as cortisol and insulin, which affect metabolism and immune function. A good night’s sleep is also linked to a more robust immune system, better decision-making, and improved athletic performance.

Work up to aiming for 7-8 hours at least 6 nights a week.

Evidence: 5️⃣

Multiple studies demonstrate that sleep quantity and quality are vital for optimal metabolism, insulin sensitivity, and glucose variability. One small study on 11 healthy young men offers a compelling glimpse at this connection: After five nights of sleep deprivation—four hours of sleep per night—study participants exhibited glucose control that resembled people with Type 2 diabetes. The men showed signs of impaired metabolism and insulin resistance, and the rate of clearing sugar out of the bloodstream was 40% slower than when they were well-rested. A recent study suggested the metabolic effects were less apparent after 3 nights of restriction on young, healthy participants. Still, overall, a large body of evidence also connects sleep loss and poor sleep to the development of obesity and diabetes.

Research Primer:

Affordability: 5️⃣

While you can certainly spend money on trackers, eye masks, or blackout curtains, for most people struggling to get enough sleep, prioritizing sleep is most important, and that’s free.

Accessibility: 3️⃣

There’s a reason more than a third of us don’t get enough sleep. In our always-on, constantly distracted culture, immersed in screens and stimuli, prioritizing the recommended seven to eight hours a night can take real discipline. And if you have small children or work night shifts, it will be significantly more challenging. For the rest of you, here are some basic tips:

Avoid eating dinner close to bedtime, and don’t snack after your evening meal.
Avoid caffeine, alcohol, and spicy foods before bed.
Set up your bedroom for sleep by keeping it cool and removing distracting lights. You can also try a white noise app on your phone or buy cheap earplugs.
Build a habit of regular sleep and wake times and resolve to stick with them. Research shows that regularity also matters for health.

Read more:

⚖️ Manage weight

Effectiveness: 5️⃣

The mechanisms involved in weight management are more complicated than the outdated model of calories-in-calories-out has led us to believe initially. Instead, complex hormonal processes are at play with weight gain and loss. However, having obesity or being overweight is a risk factor for several chronic conditions, including cardiovascular disease, cancer, Type 2 diabetes, and even premature death. Excess fat secretes hormones associated with insulin resistance and worsening metabolic health. Losing excess fat, on the other hand, has beneficial effects on metabolic health. Even a 5% weight loss helps reduce disease risk factors.

Evidence: 5️⃣

Multiple studies show the benefits of weight loss for those who have obesity or are overweight. For example, a 2018 study used data from the National Health and Nutrition Examination Survey to examine nearly 8,000 adults with obesity or who were overweight. The researchers found that all long-term weight loss thresholds (from 5% to greater than 20%) were associated with improvements in participants’ metabolic risk scores. However, achieving a weight loss of 15% or more produced the most favorable results.

Research Primer:

Affordability: 4️⃣

Depending on your methods, losing weight may require some investment. For example, moving away from ultra-processed convenience foods toward healthier meals may increase your grocery bill, and you may benefit from the structure of an app or fitness class. But you can also save money by doing free exercise and cutting back on expensive soda and desserts. If you need a costlier intervention like nutrition counseling, your insurance may cover it, or you may be able to use HSA/FSA funds.

Accessibility: 2️⃣

If losing weight were easy, the number of American adults with obesity or overweight wouldn’t be three in four. In our modern hyper-caloric, sedentary, toxin-filled environment, it can take real effort to maintain a healthy weight, much less lose those extra pounds. The good news: there’s some evidence that lifestyle change and behavior modification can be durable solutions.

Read more:

Level 2: The Explorer

If you’re someone who fairly consistently nails the basics and has a growing interest in health and how to improve it, this is your tier. As you start reading or listening to more sources about health, you’re encountering new diets, tests, or lifestyle suggestions; you’re open to adding more to your routine but still want high-reward interventions.

These activities are still mainly about overall health, not optimizing or biohacking. While these are not as foundational as Tier 1, they’re all reasonably well-established as having benefits, and you could add all to your routine with little wasted effort.

Expected outcomes:

Improved biomarkers and weight management
Increased levels of fitness and cardio health

🥩 Aim to eat more fiber and protein

Effectiveness: 4️⃣
Evidence: 4️⃣
Affordability: 4️⃣
Accessibility: 3️⃣

Why Protein Matters for Metabolic Health

When we eat protein, we’re consuming amino acids that help build the proteins our body needs to create and repair every kind of tissue, including muscle. Muscle tissue is crucial for metabolic health, as it is an excellent sink for glucose, often without insulin. Eating protein in our meals also helps slow glucose absorption and makes us feel full—both factors that can promote stable glucose.

How to get enough protein

Protein needs vary widely, but holistic nutritionist Kelly LeVeque generally recommends 0.75g per pound of body weight.
Distribute protein intake across meals, aiming for 20-30g per meal.
Eat protein-rich snacks like jerky, chickpeas, and nuts.
Add protein powder to shakes or smoothies.

Research Primer:

Why Fiber Matters for Metabolic Health

Although fiber is a carbohydrate, it mostly passes through your digestive system intact, so it doesn’t raise glucose levels. In fact, it helps slow glucose absorption and can make you feel full, so it’s a great addition to other carbs. Finally, fiber feeds the gut, producing beneficial short-chain fatty acids that promote a healthy microbiome.

How to get enough fiber

Levels advisors recommend aiming for up to 50g of fiber per day.
Chia is one of the best low-carb sources, along with flaxseed and beans.
Favor high-fiber, low-sugar fruits like avocado and raspberries.
If you use supplements, avoid those with added sugar.

🚴‍♀️ Do 150 minutes of Zone 2 exercise a week

Effectiveness: 5️⃣
Evidence: 5️⃣
Affordability: 5️⃣
Accessibility: 3️⃣

If Zone 2 exercise sounds technical, don’t worry; it’s not. It simply means moving at a pace that elevates your heart rate while going slow enough that you can still carry a conversation. Think brisk walking or light jogging.

Zone 2 gives you all the health benefits of exercise, such as improving the efficiency of your heart, reducing blood pressure, and lowering the risks of cancer, diabetes, and early death. But unlike higher-intensity sessions, which can leave you feeling wiped out, cause soreness, and require days to recover, Zone 2 hits a sweet spot that lets you reap the exercise perks without overtaxing yourself, making it a more sustainable practice. It also helps you build endurance and achieve metabolic flexibility, which is when your body can easily switch between burning carbs and burning fat for fuel.

Some experts say Zone 2 sessions of 20 minutes or more help increase mitochondria (the powerhouse of cells) and insulin sensitivity. If you’re starting to aim for some Zone 2 minutes, a heart-rate monitor can help, and they’re cheap.

Research Primer:

Exercise sustains the hallmarks of health (A primer on the benefits of moderate-intensity [Zone 2] exercise)
Beyond the Calorie Paradigm: Taking into Account in Practice the Balance of Fat and Carbohydrate Oxidation during Exercise? (A look into metabolic flexibility, which Zone 2 exercise helps you achieve)

😱 Actively work to reduce stress

Effectiveness: 5️⃣
Evidence: 5️⃣
Affordability: 5️⃣
Accessibility: 3️⃣

Prolonged exposure to stress can cause changes in the body’s physiology, including elevated levels of the stress hormone cortisol, which can lead to inflammation, high blood pressure, and weakened immune function. Chronic stress has also been linked to a range of health problems, including anxiety, depression, heart disease, diabetes, and obesity.

Stress prompts a hormonal response in the body that affects glucose levels. When you’re feeling frazzled or panicked, your body readies itself to fight off a threat by leaving ample glucose in your bloodstream for your muscles to use. To increase blood glucose, your body pumps out more adrenaline and glucagon, and consequently, your cells become insulin-resistant so that glucose stays in your blood. The result is elevated glucose, as illustrated in research that shows a link between perceived work-related stress and increased circulating glucose levels.

While you may not be ready to dive into yoga or guided breathwork, simple things like using a breath app on your phone, spending time in nature, or just counting to 10 to calm down are cheap and easy.

Research Primer:

📲 Try a continuous glucose monitor (CGM)

Effectiveness: 4️⃣
Evidence: 3️⃣
Affordability: 2️⃣
Accessibility: 4️⃣

CGMs have recently become less expensive (~$100) and available over the counter. A CGM is the best tool we have right now for seeing how food and behavior impact blood sugar in real time. This data helps you find foods that work best for you and determine the ingredients that tend to spike your blood sugar. Diet and nutrition are not one-size-fits-all. Instead, we have what’s called bio-individuality, which means that even when eating the same food as someone else, that food may affect you differently. Likewise, eating the same food one day or at one time may affect you differently than the next time you eat that same food based on other factors that affect glucose. Blanket-statement diet advice doesn’t account for this bio-individuality.

You don’t need to wear a CGM all the time; wearing one for just a month and using it with an app like Levels can provide valuable insights into adjusting your diet and lifestyle for better metabolic health. However, you may wish to wear one regularly or periodically to check in on how you’re doing.

A CGM and the Levels app can show you how high your glucose goes after a specific meal and how long it stays elevated. These factors tell you how effectively your body uses insulin. A CGM can also show you how the lifestyle changes you make outside of diet can impact your metabolic health. For example, you will see how walking after a meal helps bring your glucose back to baseline faster than if you were sitting on the sofa. A CGM can also show you the changes in your glucose levels after a poor night of sleep or when you’re stressed.

Extensive research exists to support CGM use in people with diabetes. And research is growing to support CGM use in people without diabetes to help prevent the development of prediabetes, which can then progress to Type 2 diabetes.

Research Primer:

⏰ Create strategies around meal timing

Effectiveness: 3️⃣
Evidence: 3️⃣
Affordability: 5️⃣
Accessibility: 4️⃣

Eating too late in the evening can disrupt sleep and negatively impact metabolic health, including blood sugar spikes. Late-night eating can also disrupt fat metabolism. A good rule of thumb is to eat at least three hours before bedtime, prioritizing protein, healthy fats, and fiber and reducing or eliminating refined carbohydrates.

When you allow this three-hour window while reducing your intake of refined carbohydrates, you help reduce the likelihood that you’ll be hankering for a bedtime snack. Protein, healthy fats, and fiber help slow the absorption of carbs into the bloodstream, which helps prevent a blood sugar spike followed by a crash that could lead to cravings. Additionally, you’re still allowing enough time for your food to digest before sleep, which helps prevent issues such as acid reflux.

Research is growing on the importance of meal timing. Although different studies suggest different meal cut-off times, research is generally consistent in showing that later is worse for your metabolic health. One reason late-night eating might have adverse effects is that the hormone melatonin, released when you’re exposed to darkness, can negatively impact blood sugar levels. Research also shows that an early dinner, compared to a late meal (6 pm vs 9 pm), improves blood glucose control for 24 hours.

Schedules and responsibilities can impact meal timing. However, creating a strategy that helps ensure an earlier dinner—or at least skipping late-night snacking—is doable for many and costs nothing.

Research Primer:

Level 3: The Enthusiast

If you regularly do all the activities above, you’re in better shape than most people. At this point, being healthy is a core part of your ritual and identity, and you may want to see how much fitter you can be. You’re not just looking to be average but want to start optimizing.

This tier of interventions may not have the immediate payoff as some of the above (though some, like weight training, will), but they are all ways to keep improving your body’s fitness when the basics have become routine. Consider these less as a prescription and more of a menu of things to try, depending on your goals and interests.

Expected outcomes:

Improved muscle mass and fitness
Fewer near-term health issues

🥗 Pay attention to your micronutrients and eat a diverse diet

Effectiveness: 3️⃣
Evidence: 3️⃣
Affordability: 4️⃣
Accessibility: 3️⃣

Micronutrients are crucial for healthy metabolic functioning, but the needs and benefits vary across vitamins and minerals. Determining if you’re deficient is challenging without specific tests. That said, eating a diverse diet will generally serve you well, helping to ensure you’re getting most of your micronutrient needs from whole foods. And it doesn’t require a significant investment, just swapping in a wider variety of fruits and vegetables.

Why do micronutrients matter? Most micronutrients are crucial links in chain reactions that regulate your body’s metabolism. Research links micronutrient deficiencies to insulin resistance and obesity. More than 94% of people in the United States are deficient in at least one micronutrient. Some of the critical micronutrients for supporting metabolic health are the following:

Vitamin D. This vitamin supports bone health, glucose management, insulin control, and immune function. Get it through sunlight exposure and eating fortified foods, trout, salmon, mushrooms, and cod liver oil.
Magnesium. This mineral improves insulin sensitivity and glucose processing and may reduce inflammation. Get it from pumpkin seeds, chia seeds, almonds, cashews, peanuts, some nut butters, spinach, soy milk, edamame, and black beans.
Selenium. This mineral is a powerful antioxidant that promotes glucose absorption without insulin. Get it from Brazil nuts (but only eat a few to avoid selenium toxicity), yellowfin tuna, halibut, shrimp, sardines, ham, turkey, and steak.
Zinc. This mineral is crucial for your body’s insulin system. Get it from pumpkin seeds, cashews, hemp, oysters and other shellfish, chicken, eggs, and beef.
Vitamin B. Vitamins B12, B6, and folate aid glucose metabolism and help produce new cells. Get your B12 from clams, wild trout, salmon, tuna, and eggs. If you’re vegetarian or vegan, you may need to add nutritional yeast to some meals or take a supplement. Get your B6 from chickpeas, yellowfin tuna, and salmon. Get your folate from spinach, black-eyed peas, asparagus, and Brussels sprouts.
Manganese. This mineral supports mitochondria by reducing oxidative stress. Get it from hazelnuts, pecans, mussels, oysters, chickpeas, and spinach.

Research Primer:

Read more:

🐟 Increase omega-3 fatty acids

Effectiveness: 3️⃣
Evidence: 4️⃣
Affordability: 3️⃣
Accessibility: 4️⃣

Omega-3 fatty acids are crucial elements of cells and metabolic pathways. They also help reduce inflammation. Temporary states of inflammation fight off disease and heal injuries, but chronic low-grade inflammation is a hallmark of metabolic syndrome. Inflammation is the root cause of many diseases, including cardiovascular disease, some cancers, and some neurological diseases. In addition to keeping pro-inflammatory prostaglandins at bay and promoting the production of anti-inflammatory prostaglandins, omega-3s combat inflammation in multiple ways.

Omega-3s may also help promote insulin sensitivity, though research is still in its early stages regarding this potential benefit. One small study showed that increasing omega-3 intake was correlated with significantly higher insulin sensitivity in overweight middle-aged men. Those who ate the highest amounts of omega-3s had 43% higher insulin sensitivity compared to those who ate the least.

Depending on your current diet, you may have to add some additional foods to your cart to get optimal omega-3s. The best sources: flaxseeds, chia seeds, basil seeds, walnuts, salmon, mackerel, sardines, rainbow trout, and herring.

Research Primer:

🛒 Eat primarily organic produce and grass-fed proteins

Effectiveness: 2️⃣
Evidence: 2️⃣
Affordability: 2️⃣
Accessibility: 3️⃣

Aiming to fill your cart with organic foods and grass-fed meats or dairy can benefit metabolic health by ensuring you’re getting the most nutrient-dense foods or at least avoiding potential toxins. Organic foods will be free (or nearly free) of chemical pesticides and herbicides, and animal sources will be free from added growth hormones and antibiotics. Meat from grass-fed livestock tends to have a higher concentration of omega-3 fatty acids and less saturated fat than grain-fed livestock. Meat from grass-fed livestock also tends to be higher in phytonutrients (beneficial plant compounds) and some micronutrients.

Buying more organic and grass-fed foods can be more expensive than buying conventionally produced or raised foods. Tips for reducing costs include buying at local farmers’ markets, enrolling in a community-assisted agricultural program (CSA), and focusing on in-season fruits and veggies.

Research Primer:

🦠 Be mindful of your microbiome

Effectiveness: 3️⃣
Evidence: 4️⃣
Affordability: 4️⃣
Accessibility: 3️⃣

Your gut contains billions of microorganisms (bacteria and fungi). Collectively, these are called your gut microbiome. An unhealthy gut microbiome can weaken your metabolic health, whereas a healthy microbiome can improve health.

Microbes produce metabolites that your cells can read. One example of a helpful type of metabolite is short-chain fatty acids (SCFAs). The bacteria in your gut ferment the fiber you consume. This fermentation produces SCFAs, which then support important incretin hormones, such as glucagon-like peptide 1 (GLP-1), which helps with glucose control, reduces inflammation, and helps reduce hunger signals.

The gut barrier is also vital to metabolic health, and a healthy gut microbiome is key to a healthy gut barrier. Your gut barrier absorbs nutrients and protects pathogens from entering the rest of the body. Animal studies show that the microbiome regulates different components of gut barrier defense.

You may not feel the effects of boosting your microbiome health (unless you’re dealing with digestive issues and notice a reduction). Focusing on your microbiome is not difficult or expensive, but it requires incorporating specific foods or supplements into your diet. You can enhance your gut microbiome and gut barrier via the following:

Research Primer:

Read more:

🏋️ Add strength training to your routine

Effectiveness: 5️⃣
Evidence: 5️⃣
Affordability: 3️⃣
Accessibility: 3️⃣

Strength training as a form of fitness produces some of the most noticeable effects, particularly in the early days. The evidence for the benefits of strength training and adding muscle on overall health, particularly longevity, is quite clear.

Our muscles help process glucose, so more muscle mass is associated with insulin sensitivity. Strength training boosts glucose uptake by increasing glucose transporters like GLUT-4 and by improving mitochondrial function. Additionally, strength training releases myokines, proteins beneficial for metabolic health. We lose muscle mass as we age; strength training can help increase muscle mass and protect against this age-related decline that can lead to frailty in later decades.

Compared to other forms of fitness, strength training can feel more daunting. You can do body-weight exercises like pushups, squats, and more. As you progress, you may want to use some weights, which adds cost. Also, proper form is essential and takes some effort to learn. One option is to invest in a few personal training sessions to learn moves you can do at home. Adjustable weights take up minimal space and allow for progressive overload (increasing reps or weight as you improve) without requiring extensive equipment. Aim for at least two full-body strength-training sessions per week.

Research Primer:

Progression models in resistance training for healthy adults
(From the American College of Sports Medicine)
Resistance training is medicine: effects of strength training on health
Musculoskeletal exercise: Its role in promoting health and longevity

🏃🏻‍♀️‍➡️ Try doing HIIT a couple of times a week

Effectiveness: 4️⃣
Evidence: 4️⃣
Affordability: 5️⃣
Accessibility: 3️⃣

Even if you love the benefits of exercise, making time to work out can be challenging. That’s the appeal of high-intensity interval training, known more commonly as HIIT. It promises the best workout in the least amount of time. And evidence suggests it delivers: In as little as eight minutes per week, it can offer many long-term benefits to metabolic health, including better glucose processing and improvements in insulin sensitivity. HIIT may even help reduce body fat. This type of workout increases the production of the fat-burning hormones catecholamines.

You’ll work hard during the brief intervals, but dozens of activities can fall within a HIIT workout, so you can find the ones you like best. Several apps offer routines and timers, and you can find dozens of workouts for free on YouTube. As a bonus, you can turn some strength-training workouts into HIIT workouts to further maximize your time. Be sure to perform lower-intensity workouts between HIIT sessions to give your body time to recover from the higher intensity.

Research Primer:

🍽️ Try intermittent fasting or caloric restriction

Effectiveness: 3️⃣
Evidence: 3️⃣
Affordability: 5️⃣
Accessibility: 3️⃣

Intermittent fasting is the practice of narrowing the time window you eat to something like six or eight hours during the day, reducing all-day (and late-night) snacking, and giving your body a rest from processing glucose.

Fasting helps the body become more metabolically flexible, efficiently switching between burning glucose and burning fat for fuel, depending on various factors. Fasting can help with weight management by reducing overall calorie consumption, burning fat when insulin is low, and stabilizing appetite.

You will likely feel the effects of intermittent fasting quickly as it changes your daily experience of food. Depending on how you do it and your goals, it will work for you, or it won’t.

Several studies point to the benefits of fasting or caloric restriction. However, what’s less clear is how much time you have to fast to see benefits, and some evidence suggests many people may not be fasting for long enough. The fasting benefits begin at around 12 hours for most people. So, even limiting food consumption to a 10-hour window (with 14 hours fasting) may have some metabolic health benefits. Try eating a slightly earlier dinner and later breakfast to get comfortable with the process. You can then narrow your feeding window as desired. A drawback of fasting is that it can be difficult for many people since eating in specific windows can disrupt family and social life.

Research Primer:

🩸 Get bloodwork, including insulin and ApoB

Effectiveness: 4️⃣
Evidence: 5️⃣
Affordability: 3️⃣
Accessibility: 3️⃣

Although glucose is easy to measure with a CGM, it is not the only biomarker that matters. Insulin, in particular, is arguably even more critical to both metabolic and overall health, and while a CGM can help you infer something about your insulin levels, a fasting insulin blood test is inexpensive (~$20) and easy to get at any lab or from your doctor. If you get just one blood test, make it insulin.

However, cholesterol is also worth tracking for its relationship to cardiovascular risk, the biggest killer in the U.S. You’ll get basic cholesterol and glucose at your annual physical. However, it’s worth the extra effort and expense to ask for apolipoprotein B (ApoB), a better measure of dangerous cholesterol.

Another biomarker that can help inform your metabolic health status is your uric acid level. A high level can cause mitochondrial dysfunction and is associated with cardiovascular disease, Type 2 diabetes, gout, kidney stones, fatty liver disease, and more. The Levels Labs 5-marker panel is $100, and you can spend $500 or more getting dozens more tests.

Research Primer:

Read more:

🚫🍸Cut your alcohol intake

Effectiveness: 3️⃣
Evidence: 3️⃣
Affordability: 5️⃣
Accessibility: 4️⃣

Alcohol can impact your metabolic health in several ways. Chronic use can lead to alcoholic liver disease and damage insulin-producing cells in the pancreas. It’s also linked to several cancers. But alcohol can also produce some problematic health effects in the short term, including disrupted sleep, which can impair glucose tolerance the next day. Alcohol consumption can also lead to weight gain in the form of empty calories and added sugar in mixers, such as fruit juices, soda, and tonic water, all of which can lead to glucose spikes. Plus, alcohol, especially beer, can contribute to a higher uric acid level, which is associated with several health issues.

A recent large epidemiological study found that no amount of alcohol is safe. And while abstaining from alcohol can cost nothing, it may require a change of lifestyle. Fortunately, there are now plenty of mocktails and non-alcoholic beers, even in bars.

Research Primer:

🧘‍♀️Try meditation and guided breathwork

Effectiveness: 3️⃣
Evidence: 3️⃣
Affordability: 5️⃣
Accessibility: 4️⃣

If you’ve been focusing on stress reduction, as noted in tier 2, you may wish to level up with a regular meditation practice or guided breathwork. Both practices, which often go hand-in-hand, can help reduce stress, which can benefit metabolic health. The more you practice these tools, the more effective you become at handling stress in the moment, which can help you flip the switch from fight-or-flight mode to a calmer state.

Meditation further helps strengthen connectivity between different brain networks and improves cognitive function.

Breathwork is often part of meditation, but you can do it anytime, anywhere, whether in traffic or in a stressful meeting. Breathwork can also help increase heart rate variability (HRV), a sign of cardiovascular health and adaptability.

To get started with meditation or breathwork, you can take classes or download an app for guided sessions. You can also find plenty of guidance for free on YouTube.

Research Primer:

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☕️ Cut out artificial sweeteners

Effectiveness: 2️⃣
Evidence: 3️⃣
Affordability: 4️⃣
Accessibility: 4️⃣

If you’ve worked hard at cutting out or reducing your intake of added sugars, as noted in tier 1, you may be ready to level up and eliminate artificial sweeteners from your diet. A common misconception is that no-calorie, non-sugar sweeteners such as saccharin (found in Sweet ’N Low), sucralose (Splenda), aspartame (NutraSweet, Equal), and acesulfame potassium (Sweet One) have no effect on metabolic health. These artificial sweeteners don’t raise your glucose, but they do have metabolic consequences, research suggests.

Over time, they influence how your body processes glucose and insulin and may contribute to obesity. According to animal studies, they can also negatively affect the health of your gut microbiome.

If you’ve been training yourself away from using added sugar, you’re already on a path to reducing sweet cravings. Take the next step by ditching artificial sweeteners.

Research Primer:

Level 4: The Expert

When health and fitness are central to your lifestyle, longevity is a tangible goal, and diving into the latest research is a fun pastime, these interventions are worth trying to find optimization around the margins. You’re in fantastic shape but looking to squeeze out incremental improvements. These interventions are likely good for you but either have increased difficulty or less evidence of real-world effect. Think of this as pure optimization.

Expected outcomes:

Exceptional levels of fitness (i.e., CrossFit, Ultrarunning)
Ideally, increased longevity and reduced disease risk

💦Boost your hydration

Effectiveness: 2️⃣
Evidence: 3️⃣
Affordability: 5️⃣
Accessibility: 3️⃣

Adequate hydration is crucial for overall health and bodily functions. Hydration impacts metabolic health by influencing glucose processing. Chronic dehydration can increase your risk for Type 2 diabetes and metabolic syndrome. Proper hydration helps maintain cell volume and function, supports enzyme activity, and affects insulin sensitivity and fat metabolism.

Staying hydrated is free if you’re drinking tap water. The average person typically doesn’t need electrolytes, with a few exceptions. You may need electrolytes if you’re engaging in endurance exercise or are otherwise highly active. A ketogenic diet can also have a diuretic effect that can contribute to the loss of electrolytes. If you do opt for electrolytes, be careful to choose options that don’t have added sugar.

Tips for staying hydrated:

Keep a refillable water bottle with you and drink throughout the day.
Avoid chugging water at meals (take small sips instead).
Space larger quantities of water 30 minutes before or after meals.
Always drink before salty meals.
Don’t let yourself get too thirsty. (If you’re thirsty, you’re already mildly dehydrated.)

Research Primer:

🛢️ Avoid seed oils

Effectiveness: 2️⃣
Evidence: 2️⃣
Affordability: 5️⃣
Accessibility: 3️⃣

Seed oils are one of the more controversial topics in nutrition. Opponents argue that their highly processed nature can produce dangerous chemicals while cooking with them. Plus, their high omega-6 content throws off our natural balance of fats. The standard American diet is characterized by a high ratio of omega-6 to omega-3s. A high ratio has been linked to death from cancer and cardiovascular disease. Boosting omega-3 intake helps lower this ratio.

Mainstream doctors mostly argue that there’s not enough evidence that seed oil consumption matters much in the real world and that they are better than other forms of fat, like saturated. Few debate that seed oils have little culinary or nutritional value, so avoiding them when you can is prudent, but cutting out every drop can be tricky because they are in many packaged and restaurant foods. A good practice for at-home cooking is to stick to non-seed oils, such as olive and avocado oil, which have health benefits. Also, watch for processed seed oils—such as Canola, corn, cottonseed, soybean, safflower, sunflower, grapeseed, and rice bran oils—on food packaging and seek alternatives.

Research Primer:

☀️ Add regular light and cold exposure to your day

Effectiveness: 2️⃣
Evidence: 2️⃣
Affordability: 4️⃣
Accessibility: 3️⃣

Both light and cold exposure (mostly cold plunge) have strong physiological cases for why they are good for you, but these practices are lighter on research proving their effects. Even Peter Attia, MD, says cold plunging likely doesn’t impact metabolic health (though he likes it for other benefits, like mood).

The case for sun exposure is that vitamin D is a crucial micronutrient many of us are deficient in, and sunlight is a better source than supplementation. But exactly how much you need is hard to pin down. Another practice related to light that has increasing research behind it is the need for exposure in the morning. Via a chain reaction from our eyes, morning sunlight signals our brain’s suprachiasmatic nucleus (SCN), the body’s master clock, which is involved in our circadian rhythm. Our circadian rhythm affects food intake, insulin sensitivity, glucose control, and more. Animal studies show that morning sunlight exposure lowers glucose levels and weight and boosts mood.

Both sun and cold can be cheap and easy to get more of, although sun exposure may be more or less available depending on your location. Cold exposure is just uncomfortable for most people (at least at first). To start simple and cheap, switch the tail end of your shower to a blast of cold. If you like it, you can find a business that offers cold plunging or invest in a home cold-plunge system.

Research Primer:

Read more:

☠️ Actively reduce your exposure to environmental toxins

Effectiveness: 2️⃣
Evidence: 3️⃣
Affordability: 3️⃣
Accessibility: 1️⃣

We should pay a lot more attention to toxins than we do because, collectively, they are a massive problem for society and our overall health. Toxins are often endocrine-disrupting chemicals, or “obesogens,” that disrupt reproductive hormones, increase risk for obesity, contribute to inflammation, and impact our overall metabolic health.

However, the particular effectiveness of reducing one or two products for any specific individual is more complicated to pin down. Swapping out products in your home for cleaner versions is likely helpful but can be expensive, and knowing where to start or how much reduction you need for improved health is tricky. Still, choosing the non-plastic version or looking for a no-BPA label never hurts. You can also take steps to actively choose products (cleaning, personal care, baby needs, pet needs, and more) that the Environmental Working Group (EWG) has verified.

Research Primer:

Childhood Ingestions of Environmental Toxins: What Are the Risks?
(Although this review focuses on children, it describes many of the origins and effects of environmental toxins relevant to adults.)
Fertility loss: negative effects of environmental toxicants on oogenesis
Inhaled toxins: A threat to male reproductive health

💊 Try taking supplements

Effectiveness: 3️⃣
Evidence: 2️⃣
Affordability: 2️⃣
Accessibility: 2️⃣

Ideally, we would get optimal amounts of micronutrients from food. However, sometimes we need supplements to help support our micronutrient intake, combat inflammation, and improve metabolic health. Many people in the United States are deficient in certain vitamins and minerals because of diet quality. However, even those with a relatively healthy diet may fall short because of declining soil quality and inadequate nutrient absorption.

Which supplements you take and what dosage should be guided by research and lab testing. Our needs are highly individual and based on current nutritional intake, lifestyle factors, genetics, and health status. If you’re considering taking supplements, work with a doctor to determine your specific needs, if any, and to avoid interactions with medications. Your physician can also recommend a reputable third-party tested brand.

Taking supplements requires a daily commitment, and figuring out which ones you need and finding good brands can take work. And good supplements can be expensive. Focusing only on what you need can help keep the added expense in check. Some of the best supplements for metabolic health include alpha-lipoic acid, vitamin D, curcumin, magnesium, omega-3 fatty acids, selenium, zinc, vitamin C, and CoQ10. These nutrients may combat inflammation and help regulate blood sugar.

Research Primer:

🫙Add vinegar to meals

Effectiveness: 2️⃣
Evidence: 2️⃣
Affordability: 5️⃣
Accessibility: 2️⃣

In addition to eating for more stable blood sugar, we can consume foods and beverages that help improve glucose control. One option is ingesting vinegar before or during a meal, which may lower post-meal glucose levels by 20% when consumed with a meal of complex carbs.

The studies supporting vinegar’s benefits are small, and study participants aren’t consuming typical meals. However, the evidence suggests that vinegar may help with blood sugar control, likely because the acetic acid slows gastric emptying and increases glucose uptake by cells. It’s unclear how big a difference this will make on your glucose curve in practice.

Incorporating vinegar into your diet is inexpensive (a bottle of apple cider vinegar will last a while). Still, many people dislike the taste, and it’s challenging to do on the go. Here are a few strategies to consider when including vinegar before carbs.

Add a vinegar-based dressing to your salad, and eat your salad before your carbs.
Drizzle vinegar over steamed or roasted veggies.
Dilute four teaspoons of apple cider vinegar in water and consume just before eating.

Research Primer:

Read more: Does vinegar really lower blood sugar?

🔄 Try carb cycling

Effectiveness: 2️⃣
Evidence: 2️⃣
Affordability: 4️⃣
Accessibility: 1️⃣

Carb cycling generally refers to eating a low-carbohydrate diet most of the time while incorporating short periods of increased carb intake. What’s the point? Carb cycling is a strategy that may benefit highly active people and athletes who want to boost their carb intake before intense training days or events. Carb cycling may also help those who struggle with a strict ketogenic diet and those on a low-carb diet who struggle to maintain hormone balance.

A low-carbohydrate diet shifts metabolism, where instead of burning glucose from carbs, your body shifts to burning fat and ketones for fuel. This switch can aid in weight management and support training by increasing your metabolic flexibility, when the body becomes more efficient at shifting from burning carbohydrates to burning fat. Consuming carbs at carefully planned intervals can help muscles refill with stored glucose in the form of glycogen. That glycogen can then aid high-intensity or endurance efforts. The evidence for carb cycling is still in its preliminary stages. However, studies show the benefits of eating low carb, building metabolic flexibility, and creating strategies around carb consumption to benefit performance.

Carb cycling involves strategic planning around diet and activity, which can be complicated. And eating low-carb can increase your grocery bill. Your carb cycling schedule may be different than the next person’s based on the types of workouts you do. If you’re considering carb cycling as part of your metabolic health overhaul, work with a registered dietitian who is familiar with the concept and can help tailor strategies to help you reach your goals.

Research Primer:

🚴 Try exercising in a fasted state

Effectiveness: 1️⃣
Evidence: 1️⃣
Affordability: 5️⃣
Accessibility: 3️⃣

Exercising in a fasted state means working out after not eating for at least 8 hours. The strategy forces your body to rely more on fat than glucose (whether in the bloodstream after eating or stored in muscle as glycogen) for fuel. When your body relies more on fat, you increase fat-burning during your workout, but not necessarily overall. Fasted exercise may also have benefits for insulin sensitivity and blood sugar management. However, the strategy may negatively impact performance, specifically for workouts that last longer than an hour.

Research on whether exercising fasted is beneficial is still limited and ongoing. And whether it is helpful for you will depend on individual factors, including preference. If exercising fasted leads to impaired performance, you may wish to exercise in a fed state. Exercise itself improves insulin sensitivity and has many other health benefits, whether you’re fasting or have recently eaten a meal. Exercising fasted doesn’t come at any monetary cost. However, it may take additional effort and motivation on your part.

Research Primer:

Take control of your metabolic health

Levels help you see how food and lifestyle affect your health through macro tracking, habit-building, and customized insights and advice. Levels members can also incorporate biomarker data like real-time glucose and metabolic blood testing for an even more personalized experience. Click here to get started with Levels.