Universal Nutrition Doesn’t Exist: Population Genetics Have Already Proven It

by Laurent Glatz – for Athletic Carnivore

The statement might sound almost dangerous to say, yet it’s simply biological: not all humans respond the same way to the same foods.

This observation does not diminish human equality. It only dispels a modern nutritional illusion. For decades, we’ve searched for a perfect plate for everyone, as if evolutionary history, enzymes, genes, microbiome, physical activity, climate, and past dietary exposure didn’t matter. But biology doesn’t operate on universal slogans. It works through adaptations.

A food can be traditional for one population, poorly tolerated by another, neutral for some individuals, and disastrous in a context of insulin resistance. Universal nutrition reassures institutions. It simplifies recommendations. But it does not describe the real human body.

Milk Is Not an Opinion, It’s an Enzyme

The clearest example is lactose. In all human infants, the enzyme lactase allows digestion of milk sugar. But in a large part of humanity, lactase activity decreases after weaning. Some populations, especially those with pastoral histories, have developed lactase persistence into adulthood. Others much less so.

This means a glass of milk is not the same biological event for everyone. For someone who retains strong lactase activity, it can be properly digested. For another, it can cause fermentation, bloating, diarrhea, pain, and digestive inflammation.

General nutritional discourse talks about milk as a food. Biology first asks: do you have the enzyme to handle it?

This difference is essential in the Athletic Carnivore logic. Dairy products may be “animal” on paper but blocking in reality. For some, cheese fuels hunger, slows weight loss, triggers compulsive eating, and blurs satiety. For others, a bit of butter or ghee remains neutral. The question isn’t just the food category. The question is the individual response.

Starch and the Trace of Agriculture

Starch offers another example. The AMY1 gene, linked to salivary amylase, varies in copy number among individuals and populations. Groups historically exposed to starch-rich diets often developed a higher capacity to begin its digestion right in the mouth.

But this adaptation doesn’t turn modern starch into a neutral food for everyone. Traditional rice, consumed in a context of intense physical activity, low ultra-processing, and limited caloric excess, does not have the same effect as a chain of cereals, bread, cookies, sugary drinks, and snacks in a sedentary lifestyle.

Genetics provides a margin. Modern lifestyle can destroy it.

This is where universal recommendations become dangerous. Telling everyone that cereals must be the dietary base ignores insulin, glycemic load, activity level, muscle mass, family history of diabetes, stress, sleep, and the real capacity to oxidize carbohydrates.

Alcohol, ALDH2, and Immediate Proof

The ALDH2 variant, common in East Asia, shows even more clearly that nutrition is enzymatic. Reduced activity of this enzyme prevents efficient metabolism of acetaldehyde, a toxic intermediate product of alcohol. Facial flushing, palpitations, discomfort: the body responds immediately.

Same molecule. Different response. Same glass. Different physiology.

If we accept this obvious fact for alcohol, why do we often refuse to admit it for carbohydrates, dairy products, fats, or plant foods rich in defensive compounds?

Marine Lipids and Local Adaptations

Arctic and maritime populations have long lived with high intakes of marine animal products: fatty fish, marine mammals, fish eggs, offal, fats rich in long-chain omega-3s. Again, we observe adaptations in certain lipid metabolism pathways.

This doesn’t mean everyone should copy an Inuit diet or that a modern Inuit is automatically protected against industrial food. It means dietary history leaves marks. The human body is not a single model taken from a laboratory.

The Moral Trap

Why does this topic cause so much tension? Because we often confuse biological difference with human hierarchy. Yet these are two radically different things. Saying some digest lactose better, others tolerate starch better, some metabolize alcohol poorly, or some populations have specific lipid adaptations says nothing about people’s value. It says something about their physiology.

Personalized medicine is already moving in this direction. We adapt some treatments to genetic polymorphisms. We recognize differences in drug metabolism. We talk about pharmacogenetics. Yet, when it comes to food, we often fall back into uniformity: same pyramid, same advice, same portions, same cereals, same dairy, same slogans.

It’s inconsistent.

Athletic Carnivore: Starting from the Terrain, Not Dogma

The Athletic Carnivore approach does not say everyone must eat exactly the same. It says we must start by removing dietary noise: sugar, ultra-processed foods, snacking, glycemic spikes, false hunger, trigger foods. Only then do we observe.

For some, a very simple base close to the lion’s diet — ruminant, salt, water — can serve as a dietary reset. Not as an eternal dogma, but as a tool to see what the body does when almost all parasitic signals are removed. For others, a gradual carnivore transition, with eggs, fish, certain animal products, and controlled reintroductions, will be more suitable.

This is where the Athletic Carnivore approach becomes interesting: it doesn’t just ask which food is good or bad, it seeks to understand what that food triggers in you.

Universal nutrition fails because it wants to answer before observing. Biology demands the opposite: observe first, personalize later.

The real question is not: “What is the best diet for humans?” The real question is more demanding: “What dietary environment allows your biology, with its heritage and current terrain, to become readable again?”

#PersonalizedNutrition #Genetics #Lactose #AMY1 #ALDH2 #Insulin #LowCarb #Carnivore #Metabolism #AthleticCarnivore