Identical twins Hugo and Ross Turner completed a 12-week dietary study, consuming roughly 3,500 calories daily under separate nutritional regimes – one high in carbohydrates, the other high in fat – while maintaining an identical endurance training schedule, researchers at King’s College London have confirmed.
The study, conducted in partnership with Loughborough University in the UK, aimed to minimize variables and assess the distinct physiological impacts of the two diets. Both twins received meals from a chef-prepared delivery service, supplemented with protein shakes and snacks. Hugo Turner consumed a diet prioritizing fats, while Ross Turner focused on carbohydrates, differing by approximately 500 calories in macronutrient allocation.
Hugo, adhering to the higher-fat diet, experienced a 59 percent increase in strength, alongside a 2.7kg increase in body mass. Ross, on the carbohydrate-focused plan, saw a 56 percent strength increase and a modest 0.2kg gain in body mass, according to results published on January 22, 2025.
Beyond quantifiable metrics, the twins reported differing subjective experiences. Hugo described an initial adjustment period with cravings for meat and dairy, followed by increased energy levels and improved performance during workouts as his diet shifted towards fruits, legumes, nuts, and plant-based alternatives. Ross reported less consistent energy levels throughout the day and occasional feelings of not reaching peak performance during training sessions.
Perhaps the most significant divergence emerged in their gut microbiomes. Researchers observed notable changes in Hugo’s gut bacteria following the transition to plant-based proteins, with modifications linked to increased resistance against chronic diseases such as obesity and type 2 diabetes. The National Institute of Health and Medical Research has highlighted the importance of the microbiome in preventing metabolic diseases.
The Turner Twins, born October 22, 1988, are known for their pioneering expeditions, including rowing the Atlantic Ocean in 2011-12, setting a record as the youngest four-man crew to do so, and as the first twins to row any of the world’s oceans. Hugo Turner suffered a neck injury at age 17, requiring reconstruction, and the twins have since supported spinal research charities. They have also participated in research studies at King’s College London’s Department of Twin Research, earning them the moniker “Adventure Guinea Pigs.”
The twins previously climbed Mount Elbrus, allowing King’s College London and GlaxoSmithKline’s Human Performance Lab to study the effects of altitude on the human body, comparing modern mountaineering gear with replicas from George Mallory’s 1924 Everest expedition. This October, the Turner Twins are scheduled to attempt Mera Peak in Nepal, continuing their scientific expeditions.
Researchers emphasize that the study does not establish a definitive “winner” between the two diets, but rather underscores the body’s nuanced response to nutritional intake. The findings suggest that a higher-carbohydrate diet may be more beneficial for high-intensity exercise, while a higher-fat diet may be better suited for prolonged, lower-intensity activities.