Overview of Why One Diet Doesn't Work for Everyone: Nutrigenomics, Microbiome Diversity & More
In this throwback interview on the Ultimate Health Podcast, Shawn Stevenson explains why there is no single “best diet” for everyone and why health is deeply personal. He shares how his own digestion problems forced him to rethink dogmatic plant-based and paleo beliefs, leading him toward a more individualized approach rooted in nutrigenomics, microbiome diversity, circadian medicine, and metabolic flexibility. The conversation blends personal story, practical nutrition strategies, and a strong call to stay open-minded as new data emerges.
Core Message: Nutrition Must Be Personalized
Shawn’s main point is that dietary success depends on the individual, not ideology.
- He moved from an ultra-processed fast-food diet to a plant-heavy/raw-food approach and initially improved dramatically.
- Later, he developed digestive issues and food sensitivities from eating too many raw foods and overly restricting whole-food categories like beans, rice, and certain grains.
- That experience taught him that even “healthy” foods can become problematic depending on the person, the gut environment, and the season/stage of life.
- He stresses that people should adapt their diet as their body changes, rather than doubling down on a framework that no longer works.
Nutrigenomics, Genetics, and Food Sensitivity
A major theme is how food interacts with genes and genetic expression.
Nutrigenomics vs. Nutrigenetics
- Nutrigenomics: food influences gene expression.
- Nutrigenetics: your genetic background helps shape which foods may work best for you.
Key idea
- Every bite of food influences every cell in the body.
- Shawn argues that modern nutrition often becomes too fragmented, treating organs in isolation instead of seeing the body as a whole system.
- He also encourages people to consider ancestry and heritage when choosing foods, since traditional diets often align better with what a person’s family has historically eaten.
Microbiome Health and Reintroducing “Feared” Foods
Shawn describes how he improved his gut health by rebuilding tolerance instead of avoiding more and more foods.
- He had a period of dysbiosis and digestive discomfort.
- A physician recommended he repopulate beneficial gut bacteria with foods like:
- beans
- sprouted grains
- resistant starches
- He initially resisted because he had become afraid of trigger foods.
- Once he reintroduced certain foods and supported his gut more broadly, his digestion improved quickly.
- He emphasizes that the goal is not to “kill all bad bacteria,” but to restore balance in the microbiome, virome, and broader internal ecosystem.
Circadian Medicine: Timing Matters
Shawn says one of the next major frontiers in health is circadian medicine—aligning behavior with the body’s internal clock.
Morning sunlight
He recommends getting sunlight soon after waking:
- Ideally within 90 minutes to 2 hours after sunrise
- Even 5–10 minutes can help
- If you can’t get outside, ambient light through windows is still better than nothing
Why it matters
- Morning light helps regulate cortisol rhythms
- It supports better evening sleep
- It helps synchronize body clocks that affect metabolism, inflammation, and energy balance
Practical note
- In northern climates or cold weather, you can still:
- open blinds and windows
- sit by natural light
- take a short morning walk
- use light boxes when necessary for seasonal issues
Exercise Timing and Sleep Quality
The interview highlights research showing that when you exercise can affect recovery and sleep.
Best timing
- Morning exercise tended to produce:
- better sleep quality
- more time in deep sleep
- better evening blood pressure reduction
Shawn’s take
- Morning movement does not have to be intense:
- a 5–10 minute walk
- mobility work
- light rebounder work
- Evening workouts are not “bad,” but if possible, earlier movement better supports circadian alignment.
Intermittent Fasting, Metabolic Flexibility, and Fat Loss
Shawn gives a nuanced explanation of intermittent fasting.
What fasting does
- It can shift the body from storing fat to mobilizing stored fat for fuel.
- It can improve insulin sensitivity and help preserve muscle in the short term.
- It is not magic by itself; outcomes depend on the overall pattern and context.
Important distinction
- He warns against long-term calorie restriction without purpose.
- The goal is to use fasting strategically, not obsessively.
His personal routine
- He typically waits a couple of hours after waking before his first coffee or calories.
- His eating window is often more consolidated, which supports circadian health and metabolic efficiency.
Coffee, MCT Oil, and “Fasting Mimicking” Nutrients
Shawn challenges the idea that any calorie during a fast is automatically “bad.”
Coffee
He explains that coffee can:
- stimulate satiety hormones
- support fat mobilization
- activate metabolic pathways like AMPK
- potentially increase brown fat activity
MCT oil
- MCTs can rapidly increase ketone production
- They may support fat oxidation while preserving muscle
- In some contexts, they function as a fasting-mimicking nutrient
Bottom line
- Black coffee, tea, and water are fasting-friendly.
- Adding fat or protein technically breaks a strict fast, but may still support a different kind of metabolic benefit.
Protein, Post-Workout Nutrition, and Muscle Preservation
Shawn strongly pushes back against the idea that protein is optional.
- Protein is a foundational building block for:
- muscle
- hormones
- enzymes
- tissue repair
- He argues that many people have been underfed on protein and overexposed to ultra-processed foods.
- Post-workout is a time when the body is especially ready to use protein and carbohydrates effectively.
- If you fast after training, there may be benefits like increased growth hormone, but you still need to meet your protein needs across the day.
Brain Health, Omega-3s, and the Fish Oil Debate
The conversation also turns to fats, especially those needed for brain health.
Why DHA and EPA matter
- These fats are critical structural components of the brain.
- Low intake is associated with poorer cognitive outcomes and brain shrinkage risk.
- Shawn notes that plant-based omega-3 precursors like ALA may not convert efficiently enough in many people.
Food-first sources
He favors getting brain-supportive fats from:
- fatty fish
- fish roe/caviar
- eggs
- grass-fed animal foods
Supplements
- He is generally food first, but acknowledges that supplements can be useful when food quality is limited.
- He sees fish oil as a food-derived concentrate, but notes legitimate concerns around:
- sustainability
- oxidation/purity
- environmental toxicity
Anti-Dogma and the Need for Flexibility
One of the strongest recurring themes is intellectual humility.
- Shawn shares how he used to be rigid and dismissive of other approaches.
- He now believes that:
- no one diet works for everyone
- almost every food framework has some value
- people should stay open to changing their mind when their body gives new feedback
- He critiques the culture of health “tribalism,” where people fight over details while ignoring the much larger issue of ultra-processed food consumption.
Main Takeaways
- There is no universal best diet. Personal biology, ancestry, gut health, and life stage all matter.
- Food affects gene expression. Nutrition is not just calories; it’s biological signaling.
- Microbiome diversity matters. Sometimes healing means reintroducing foods, not removing more.
- Timing matters. Morning light, early movement, and eating windows all influence metabolism and sleep.
- Protein and healthy fats are essential. Especially for muscle, brain health, and resilience.
- Stay flexible. The healthiest approach is often the one that evolves with your body.
Practical Recommendations from the Episode
- Get morning sunlight as soon as reasonably possible after waking.
- Add light movement early in the day.
- Consider a more consolidated eating window rather than grazing all day.
- Don’t fear whole foods indefinitely—retest and reintroduce when appropriate.
- Prioritize protein and omega-3-rich foods for long-term health.
- Be willing to question your own assumptions about diet and wellness.