Weight loss could vary according to people's genes, new research suggests.
Scientists gave animals diets typically followed by humans and revealed it produced very different results according to their DNA, with some becoming obese and others being made healthier, a study found.
Among those given a typical, 'healthy' Mediterranean diet, some saw improvements to their blood pressure and cholesterol levels, while others gained weight, depending on their genetics, the research adds.
Those given an American-style diet high in fat and refined carbohydrates, either became severely obese or experienced little change aside from an increase in liver fat, the research adds.
Results also reveal some animals became healthier when eating an Atkins-style low-carb, high-protein diet, yet others gained weight and suffered liver damage.
The same was true for those following the Japanese way of eating, which, in humans, typically involves eating sushi for its low-fat, high-omega 3 health benefits.
Lead author William Barrington from the Texas A&M College of Medicine, said: 'My goal going into this study was to find the optimal diet. I wanted to get the diets as close to popular human diets as possible.
'But really what we're finding is that it depends very much on the genetics of the individual and there isn't one diet that is best for everyone.'
Genetics may cause different people to gain weight or become healthier if they eat the same
Among the four diets assessed, results vary by:Japanese diet: Although so-called 'sushi diets' are often adopted by humans for their low-fat, high-omega 3 benefits, including decreasing cholesterol and blood pressure, certain genetic traits cause animals to develop increased liver fat and organ damage. Atkins diet: The low-carb, high-protein diet made popular by its rapid weight-loss results, causes some to be made healthier, while others become severely obese, with fatty livers and high cholesterol. It also makes some animals become 'skinny fat', where they gain body fat but remain lean. American-style diet: High in fat and refined carbohydrates, this makes certain animals become severely obese, while others experience little change aside from an increase in liver fat. Mediterranean diet: Famed for its health-giving properties, the diet rich in olive oil, nuts and vegetables