Two British twins spent three months eating in opposite ways, giving scientists a rare, side‑by‑side look at what food really does to the body.
Instead of debating diets on social media, Hugo and Ross Turner turned themselves into guinea pigs, following carefully controlled vegan and meat-heavy menus while researchers tracked almost every reaction inside their bodies.
Twins, same genes, opposite plates
Hugo and Ross Turner are not your average volunteers. The British twins are adventure athletes known for polar expeditions and endurance challenges. That made them ideal candidates for a bold nutrition experiment.
For 12 weeks, under the supervision of scientists at King’s College London, the brothers agreed to live almost identical lives with one major difference: what they put on their plates.
- Hugo followed a strictly vegan diet: no meat, fish, eggs, dairy or other animal products.
- Ross ate a carnivorous, meat‑ and dairy‑rich diet, with animal products at the centre of most meals.
- Both kept the same training programme and exercise volume.
- Total daily calories were matched to keep the comparison as fair as possible.
This setup tackled one of the biggest headaches in nutrition science: people’s lives are messy. Genetics, work, sleep, exercise and stress all blur the picture. With identical twins living and training in step, researchers could focus almost entirely on the effects of food.
Same DNA, same workouts, same calories – the Turner twins turned their diets, and only their diets, into the experimental variable.
Energy highs, energy lows: how each twin felt
The first changes were not in blood tests but in day‑to‑day sensations.
Hugo, on plants only, reported a more stable energy curve across the day. He described fewer sudden hunger pangs and a smoother feeling during workouts. Long training sessions felt more manageable, and he bounced between meals with less urge to snack.
Ross, on the meat-heavy plan, felt something different: peaks and dips. Some sessions were explosive, with strong power output. Others were marked by noticeable slumps, especially later in the day. He also said his appetite came in waves, leading to periods of strong cravings.
The vegan twin experienced steadier energy and fewer cravings, while the carnivore twin rode a more uneven energy rollercoaster.
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These personal impressions matched a pattern nutritionists often see. Fibre‑rich plant foods slow digestion, leading to steadier blood sugar. Meals focused on meat and refined carbohydrates can bring faster spikes and drops, particularly when fibre and complex carbohydrates are low.
Body composition: fat down, fat up
Once researchers looked at body metrics, the contrast sharpened.
On the vegan diet, Hugo lost body fat. His overall weight did not crash, but the ratio of fat to lean mass shifted in a direction athletes usually welcome. His cholesterol numbers also headed downward, especially LDL, the type often linked to higher cardiovascular risk.
Ross, on the carnivore-style diet, gained muscle, which was expected given his high protein intake and serious training. Yet that came with a catch: body fat also increased. His weight went up, but not all of it was the kind you want for performance or long‑term health. His cholesterol levels, interestingly, stayed roughly flat during the 12‑week period.
Plants nudged one twin toward lower body fat and lower cholesterol; meat helped the other build muscle but also added extra fat.
What this really says about vegan vs meat-based diets
The data do not crown one diet as a universal winner. The vegan plan leaned toward better cardiovascular markers and leanness. The meat‑heavy approach seemed better for muscle gain, at least in the short term, but carried a higher fat cost.
The more nuanced lesson is that nutrition goals matter. Someone chasing lower cholesterol and a leaner profile might benefit from a plant‑centred pattern like Hugo’s. A strength athlete focused purely on muscle mass might see faster gains on a high‑protein, meat‑rich plan like Ross’s, provided they keep a close eye on fat gain and blood markers.
The gut story: when microbes meet menus
Beyond visible changes, the Turner experiment opened a window onto the gut microbiome – the trillions of bacteria living in the intestines that influence digestion, immunity and possibly mood.
Researchers observed that Hugo’s vegan diet clearly changed his gut bacteria. Diversity increased in some areas but also became less stable from week to week. His microbiome shifted into a new pattern that seemed highly responsive to what he ate each day.
Ross, on the meat-based diet, showed a more stable microbiome over the 12 weeks. The mix of bacteria moved less dramatically, suggesting that his gut community was less shaken by the change in menu.
The vegan diet rewired the gut microbiome more intensely, while the carnivore diet kept the microbial picture steadier but less dynamic.
These findings echo the work of Professor Tim Spector, a leading researcher in twins and gut health at King’s College London. His broader studies stress that having a wide range of plant foods tends to support microbial diversity, but sudden, drastic shifts in diet can also unsettle the gut before a new balance appears.
Why microbiome diversity matters
Scientists often talk about “diversity” in the microbiome, meaning how many different types of bacteria are present and how evenly they share space. A more diverse gut tends to correlate with better metabolic health and stronger resilience against certain diseases.
Yet diversity is only part of the story. Stability counts as well. A gut ecosystem that constantly swings can lead to digestive discomfort and unpredictable reactions to food. The Turner experiment hinted that a purely vegan pattern can change things fast, for better or worse, while a meat‑heavy diet may keep the gut more stable but not necessarily more varied.
Supplements twist the plot
The brothers did not stop after 12 weeks. They later ran another test, this time focusing on supplements over six months.
Hugo took vegan supplements derived from algae and plant oils, including sources of vitamin D3 and omega‑3 fatty acids. Ross used traditional animal‑based products, such as fish‑oil capsules and standard vitamin formulations.
In a surprise to many, blood tests showed Hugo ending up with higher levels of both vitamin D3 and omega‑3 than his meat‑eating brother. That result challenges the idea that vegans must always be nutritionally disadvantaged and that fish‑based supplements automatically deliver better numbers.
Smartly chosen plant‑based supplements can match, and sometimes overtake, animal‑derived products on key nutrients like omega‑3 and vitamin D3.
Personalised nutrition beats diet wars
The Turner twins’ experiment has fueled public curiosity because it sidesteps ideology. There was no attempt to “win” the vegan versus carnivore argument. Instead, the focus lay on measurable, trackable outcomes in two genetically identical bodies.
The results point strongly toward personalised nutrition. The vegan diet clearly suited Hugo’s energy levels and blood lipids. Ross tolerated his meat‑heavy plan without an immediate spike in cholesterol and built muscle effectively, though he also carried more fat by the end.
Researchers increasingly argue that our ideal diet depends on factors such as genetics, existing microbiome, level of physical activity and medical history. What looks like a miracle plan for one person can stall or even backfire for another.
| Aspect | Hugo (vegan) | Ross (carnivore) |
|---|---|---|
| Energy levels | More stable, fewer cravings | Peaks and dips, stronger swings |
| Body fat | Decreased | Increased |
| Muscle mass | Maintained or modest gain | Clear gain |
| Cholesterol | Went down | Largely unchanged |
| Gut microbiome | More change, less short‑term stability | More stable, fewer shifts |
| Supplement response | Higher D3 and omega‑3 with vegan products | Lower levels despite traditional fish‑based supplements |
What this means if you are rethinking your plate
For readers weighing vegan, meat-heavy or mixed diets, the Turner case offers a few grounded takeaways rather than strict rules.
- If you aim for weight loss and lower cholesterol, a plant‑centred diet rich in beans, whole grains, nuts and vegetables can tilt your body in that direction.
- If you are focused on muscle gain, high protein intake matters; it does not have to come only from meat, but animal products make it easier for many people.
- Gut health responds strongly to what you eat. Gradual shifts, with plenty of different plant foods, tend to support a more resilient microbiome.
- Supplements can close gaps on both vegan and meat‑based diets, but quality and form of nutrients matter as much as the label.
Anyone considering a radical change, such as going fully vegan or embracing a carnivore trend, can use the twin study as a kind of simulation. Imagine your own training, sleep and stress levels laid over Hugo or Ross’s results. A person with high cholesterol and a sedentary job has different needs from a weightlifter or an ultra‑runner.
Terms like “microbiome”, often thrown around vaguely, have very concrete effects here. These microbes help break down fibre, produce certain vitamins, train the immune system and may influence how quickly you gain or lose weight. Supporting them often comes down to variety: different plants, different fibres, different colours on your plate.
The Turner twins showed that you do not need to join a diet tribe to see real change. You need a clear goal, a way to track your own response, and enough flexibility to adjust when your body sends a message, whether that message looks more like Hugo’s charts or Ross’s.
Originally posted 2026-03-12 17:28:18.