Vegan vs. Carnivore: Twin Study Uncovers Surprising Effects on the Body

[Article déjà publié le 29
août 2025]

Food raises passionate debates, between ethical convictions, environmental considerations and promises for health. But beyond ideologies, what do the biological effects of a diet on the human body really reveal? By confronting two opposing approaches through a unique experience, a duo of identical twins sheds new light on the impacts of veganism.

When two twins become guinea pigs for their diet

Hugo and Ross Turner, British adventurers known for their extreme expeditions, agreed to test two diametrically opposed diets. For twelve weeks, Hugo followed a strictly vegan diet, while Ross focused on a diet high in meat and dairy. Their lifestyle, sports program and calorie intake remained the same, which provided a rare testing ground for the researchers at King's College London who supervised the trial.

From the first weeks, the effects on their bodies were felt. Hugo, deprived of animal products, quickly noticed greater energy stability. He explained that he felt fewer cravings and better endurance in his workouts. Ross, on the other hand, saw his energy fluctuate wildly, sometimes peaking during his workouts, sometimes dropping markedly.

What veganism reveals about energy and intestinal flora

Beyond their sensations, the study highlighted physiological differences. Hugo, on his vegan diet, lost body fat and had lower cholesterol levels. Ross, for his part, gained muscle, but also fat, without any change in his cholesterol. These results, reported by Business Insider, illustrate the extent to which two dietary patterns can differently shape an organism that is genetically identical.

Researchers were particularly interested in the intestinal microbiota. Experience has shown that a vegan diet modifies bacterial diversity in a notable way, sometimes to the detriment of stability, while a meat diet tends to maintain a more constant flora. These observations are consistent with the work of Professor Tim Spector, a specialist in twinning and the microbiota, who underlines the importance of dietary diversity in intestinal balance.

Towards personalized nutrition rather than a single diet

The Turners didn't stop at this one experience. More recently, they extended their tests by comparing food supplements of plant and animal origin for six months. According to The Economic Times, Hugo, who took vegan supplements based on algae and vegetable oils, saw his vitamin D3 and omega-3 levels surpass those of his brother, who was a fan of traditional fish-based supplements.

These results invite us to rethink the question more broadly. Veganism can improve certain parameters such as energy or lipid composition, but it can also reduce bacterial diversity, while the meat diet maintains intestinal stability but increases fat mass. The twins' experience shows above all that each organism reacts differently and that there is no absolute truth. The future of nutrition seems to lie in the fine adaptation of food to individual needs, combining variety, quality and balance between plants and animals.