How food as medicine supports longevity and better metabolic health

Originally published on June 21, 2022

Food as medicine starts with one question: how much can what you eat change inflammation, insulin resistance, recovery, and long-term disease risk? In Episode 178 of the WHOOP Podcast, Kristen Holmes, Global Head of Human Performance, Principal Scientist at WHOOP, talks with Dr. Julie Foucher, a family physician at Wild Health and four-time top-five finisher at the CrossFit Games, about how nutrition shapes health from the cellular level up. Foucher explains why genes are not destiny, how meal timing and fasting can affect sleep and recovery, which foods are most likely to reduce chronic inflammation, and why nutrition changes work best when you pair them with data, lab work, and a clear reason for making the change.

To listen to Episode 178 of the WHOOP Podcast in full, head to the WHOOP Podcast on YouTube.

What does food as medicine actually mean?

Food as medicine means food is both fuel and biological instruction. Foucher’s point is that meals do more than provide calories, they supply the raw material and the signals that influence proteins, metabolic pathways, and tissue repair.

Her own path explains why this idea lands. Before CrossFit and medical training shifted her perspective, Foucher says she treated healthy eating as a restriction problem. Performance changed that. Once the goal became lifting more, learning skills, and recovering well enough to train again, food stopped being something to minimize and became something to use well.

That framing matters beyond sport. If food becomes the basis for cells, hormones, enzymes, and repair, then nutrition belongs in the same conversation as sleep, exercise, and other daily inputs that shape health over time. Foucher’s version of food as medicine is not a promise that one meal fixes one disease. It is a reminder that diet influences the conditions in which health or disease develops.

As Foucher explains:

“Food is the basis for every molecule in our body. What we take in becomes our cells. It communicates to our DNA of what proteins are going to be turned on and off and which metabolic pathways are going to be activated.”

What you should take away

• Food as medicine starts with the idea that meals affect biology, not just calorie intake.
• A performance mindset can make nutrition easier to understand because it shifts the question from restriction to fueling.
• Daily eating patterns belong in the same health conversation as sleep, exercise, and recovery.

If you want to hear Foucher unpack how nutrition becomes a signal to your cells, listen to the full episode on Spotify

How do food choices affect genes, insulin resistance, and chronic disease?

Once food is framed as an input, the next question is what that input changes over time. Foucher’s answer is that diet affects chronic disease risk partly through epigenetics, the process by which environment influences gene expression.

In practice, that means family history is a risk factor, not a sentence. Foucher says many people arrive in clinic assuming diabetes or heart disease is inevitable because it runs in the family. Her argument is that environment often has more day-to-day control over whether those risks are expressed. Poor diet, short sleep, inactivity, smoking, and other exposures can push the body toward insulin resistance and chronic inflammation. Better food quality, movement, and recovery habits can push in the other direction.

She repeatedly returns to insulin resistance as a common thread. In Foucher’s framework, metabolic dysfunction can later show up as obesity, high blood pressure, cardiovascular disease, kidney disease, liver disease, and even neurodegenerative decline. That same root problem may look different from person to person, which is one reason she prefers looking for early markers before disease crosses a diagnostic threshold.

That is where screening matters. Foucher calls out blood pressure, fasting glucose, hemoglobin A1c, lipids, C-reactive protein, and body composition or waist measures as useful ways to catch a slow, smoldering process early. She contrasts that with a conventional visit that often stops at whether a number still falls inside a broad normal range. If you want a related read on this metabolic lens, WHOOP has also explored food, aging, and metabolic health.

Foucher puts the point plainly:

“Our destiny is so much more controlled by our environment and how our environment impacts our genetic expression, which is the field of epigenetics.”

What you should take away

• Genes influence risk, but daily environment helps determine how that risk is expressed.
• Insulin resistance is one of the main pathways linking poor diet to chronic disease.
• Blood pressure, fasting glucose, hemoglobin A1c, lipids, CRP, and body composition can reveal trouble before a formal diagnosis appears.

If you want to hear Foucher go deeper on insulin resistance and early screening, watch the full episode on YouTube

Which foods are most likely to reduce inflammation?

From there, the practical question becomes what to eat first. Foucher’s answer is to remove the obvious pro-inflammatory inputs, then build meals around whole foods that are easier to recognize and harder to overprocess.

She starts with processed foods, refined sugar, and industrial oils such as canola and generic vegetable oils. Foucher borrows a simple rule from Michael Pollan: if something was made in a plant, be cautious about eating it, and if it came from a plant, it is usually a safer bet. That is not a perfect rule, but it is useful in a grocery store. Her version is to shop the perimeter when possible, focus on fruits, vegetables, eggs, fresh meats, nuts, and seeds, and check ingredient labels when food comes in a package.

She also gives people a practical label check. Ingredients are listed by quantity, so if sugar is one of the first ingredients, the product is carrying a heavy sugar load. Foucher likes foods with short ingredient lists and ingredients you can actually identify.

On the positive side, she points to colorful produce, berries, spices, green tea, coffee, and dark chocolate as strong sources of antioxidants. She is also specific about fish. At Wild Health, she likes the SMASH group, salmon, mackerel, anchovies, sardines, and herring, because they combine omega-3 fats with lower heavy metal exposure. WHOOP has covered a similar longevity angle in protein and skeletal muscle, where food quality and tissue health show up in a different context.

Foucher’s most concrete example is this:

“Salmon, mackerel, anchovies, sardines, and herring are going to be really high in omega-3s, which are anti-inflammatory fats, but they’re also lower in heavy metals like mercury.”

What you should take away

• Anti-inflammatory eating starts by cutting processed foods, refined sugar, and industrial oils.
• Short ingredient lists and recognizable ingredients are useful filters when food comes in a package.
• Colorful fruits and vegetables, berries, spices, and omega-3-rich fish are recurring anchors in an anti-inflammatory pattern.

If you want to hear Foucher unpack label reading and anti-inflammatory food choices, listen to the full episode on Spotify

How should meal timing and fasting fit into a healthy routine?

Food quality leads naturally to timing. Foucher’s view is that meal timing matters because circadian biology changes how the body handles food across the day.

She points to Dr. Satchin Panda’s research on time-restricted eating, especially the finding that many people spread eating across more than 15 hours. Her first recommendation is simple: start with a 12-hour overnight fast. That is a practical reset for people who graze from early morning into late night without realizing how wide the eating window has become.

Foucher also argues that earlier meals usually fit human biology better. She cites patterns seen in Blue Zones and in circadian research: larger meals earlier in the day, a lighter evening meal, and a buffer before bed. Holmes adds a clear WHOOP observation here. When people eat close to bedtime, WHOOP trends often show lower Recovery, lower HRV, higher resting heart rate, and more fragmented Sleep. Late meals do not affect everyone the same way, but the direction is common enough to watch.

Athletes make this more complicated. Someone training hard may need calories after evening sessions, especially if hunger is low during the day. Foucher does not dismiss that. She suggests experimenting with ways to eat more earlier so the whole day’s intake does not get pushed into the last few hours before sleep. She is also cautious with longer fasting windows for women, an area where coaches and researchers such as Dr. Stacy Sims have raised important concerns.

Foucher gives a clear starting point:

“Start with a 12-hour window because, as we know from Satchin Panda’s research, there’s a large portion of people who are eating more than 15 hours a day.”

What you should take away

• A 12-hour overnight fast is a practical entry point for people whose eating window has stretched across most of the day.
• Earlier meals usually align better with circadian biology than large late-night meals.
• WHOOP can help you test meal timing by comparing late eating with Sleep, Recovery, HRV, and resting heart rate trends.
• Athletes and women may need a more individualized approach to fasting than the average healthy adult.

If you want to hear Foucher go deeper on fasting and circadian rhythm, watch the full episode on YouTube

Is there one best diet for performance and longevity?

After timing comes the question people usually want answered first: which diet is best? Foucher’s answer is that there is no single prescription that works equally well for everyone, but there are common principles that narrow the field.

Those shared principles are familiar by this point: eat real food, minimize highly processed products, pay attention to meal timing, and collect enough information to see whether your approach is helping or hurting. From there, she wants people to test rather than join a nutrition identity. A vegan pattern, a paleo pattern, or a higher-fat plan can all look good on paper. The deciding factor is how your body responds.

Foucher is interested in using genetics as a clue, not a verdict. She mentions variants such as FTO and PPARG, which may influence how well someone tolerates higher saturated fat intake. That does not mean a person with one of those variants can never eat more fat. It means a keto-style plan may deserve closer monitoring through lab work, symptoms, performance, and recovery data. The same logic applies to other potential triggers, including gluten. Experiment first, then decide.

That is why Foucher likes combining subjective feedback with objective measures. Holmes mentions WHOOP data, and Foucher adds lab work, symptom tracking, and even continuous glucose monitors as ways to turn nutrition into an actual test. For related context on sustainable change, WHOOP has also covered nutrition and habit formation and nutrition, longevity, and women’s health.

Foucher’s most specific point here is this:

“There are certain variations that we call SNPs, like FTO or PPAR gamma, and the people who have those are much less likely to tolerate saturated fat in their diet.”

What you should take away

• No single diet wins for every person across performance, recovery, and longevity goals.
• Real food, fewer processed inputs, and attention to timing are common ground across most sound nutrition plans.
• Genetics can point you toward useful experiments, but lab work, symptoms, and performance data still decide whether a diet fits you.

How can nutrition support injury recovery, mental health, and lasting habit change?

Once the broad framework is in place, nutrition becomes more targeted. Foucher applies that thinking to injury recovery, mental health, and the hard problem of sticking with change long enough to matter.

For recurring injuries, she does not start with food alone. Sleep deprivation, overtraining, poor movement patterns, and a more inflammatory diet can all add up. In athletes, that combination often shows up as persistent aches before it shows up as one obvious diagnosis. She wants the root causes checked first, then she layers in specific nutrition support. For tendon issues, Foucher calls out collagen, bone broth, sardines with bones, and vitamin C as practical additions during healing. If this topic interests you, WHOOP has a related performance angle in how food fuels performance.

She applies the same systems view to mental health. Foucher points to the gut-brain connection and cites the work of Dr. Uma Naidoo, a Harvard psychiatrist who has focused on nutritional psychiatry. Her point is that food affects the microbiome, gut permeability, inflammation, and neurotransmitter production, all of which can shape mood and cognitive function.

Then there is behavior change. Foucher says the plan only sticks when the reason is personal. Instead of telling people what they should want, she asks what they want their health for. It may be playing with grandchildren, climbing a mountain, competing well, or simply feeling better day to day. Once that reason is clear, data becomes more useful. WHOOP trends, lab results, and other forms of tracking make progress concrete enough to reinforce the behavior.

Foucher explains the gut-brain piece this way:

“I think 90% or 95% of our neurotransmitters, serotonin, is produced in our gut.”

What you should take away

• Injury recovery works best when nutrition is matched with sleep, movement quality, and appropriate training load.
• Collagen-rich foods, vitamin C, and an anti-inflammatory eating pattern can support tendon healing.
• Gut health and mental health are connected through the gut-brain axis and neurotransmitter production.
• Lasting nutrition change usually starts with a personal reason for better health, then gets reinforced by data.

The bottom line

• Food acts as biological input that can influence gene expression, metabolic pathways, inflammation, and tissue repair.
• Insulin resistance is one of the main pathways linking poor diet to chronic disease across blood sugar, cardiovascular risk, and metabolic health.
• Processed foods, refined sugar, and industrial oils are common drivers of a more pro-inflammatory diet pattern.
• Blood pressure, fasting glucose, hemoglobin A1c, lipids, CRP, and body composition can reveal metabolic trouble before disease is formally diagnosed.
• A 12-hour overnight fast is a practical starting point because many people spread eating across more than 15 hours each day.
• Earlier meals usually fit circadian biology better, while late-night eating often lines up with lower Recovery, lower HRV, higher resting heart rate, and less consolidated Sleep.
• No single diet works for everyone, and genetics such as FTO or PPARG variants may change how well someone tolerates higher saturated fat intake.
• Nutrition changes last longer when they are tied to a clear personal goal and checked against real data instead of guesswork.

Frequently asked questions about things discussed in this episode

How does WHOOP help you see whether eating close to bedtime affects recovery?

WHOOP can show whether late meals line up with lower next-day Recovery. Logging meal timing in the WHOOP Journal lets you compare late eating with Sleep performance, HRV, resting heart rate, and Recovery trends over time.

What does WHOOP do for fasting experiments?

WHOOP helps you test whether a fasting routine fits your life and training load. Recovery, Sleep, resting heart rate, and HRV trends can show whether a shorter or longer eating window is supporting recovery or adding stress.

How does WHOOP fit into a food as medicine approach?

WHOOP turns nutrition changes into something you can observe instead of something you just hope is helping. When you pair food changes with Sleep, Recovery, and strain trends, it becomes easier to see whether the plan supports better health habits.

What does WHOOP track when underfueling and heavy training start to add up?

WHOOP tracks the recovery side of the equation when training stress rises and fueling falls short. Lower Recovery, reduced HRV, higher resting heart rate, and poorer Sleep consistency can all be useful signals that the whole system needs attention.

How can WHOOP Journal help with meal timing and food quality changes?

WHOOP Journal helps you connect specific nutrition behaviors with next-day physiological trends. A consistent logging habit makes it easier to compare earlier dinners, fewer late snacks, or other routine changes against Recovery and Sleep outcomes.

What does WHOOP tell you that lab work does not?

WHOOP shows day-to-day response patterns that lab work cannot capture on its own. Lab markers help identify longer-term metabolic risk, while WHOOP helps you see how behaviors such as late eating, poor sleep, or harder training affect nightly sleep and next-day recovery.

When you pair better food quality with WHOOP trends for Sleep, Recovery, HRV, and resting heart rate, nutrition stops being abstract and becomes a daily experiment you can actually learn from.