Diet success depends on your genes, study finds

'We've largely viewed diet the same way for the last 100 years – assuming that there is one optimal diet ... this is likely not the case'

One mouse got fat, while the other didn't when fed a typical Western diet (William Barrington, North Carolina State University)

There is no perfect diet that can help anyone maintain a healthy weight, scientists have said, after carrying out a study which suggests food affects individual animals differently based on their genes.

The researchers fed four groups of mice on different kinds of food – Western, Japanese, Mediterranean and an Atkin’s-style diet high in fat and low in carbohydrate.

Red wine extract was added to the Mediterranean one and green tea extract to the Japanese one so that the food closely mirrored typical human diets.

The mice were allowed to eat what they wanted, but the scientists recorded how much.

Six months later, they discovered that one genetic strain of mice became obese and got liver disease after eating the Western food, but had no adverse health effects from eating the Atkin’s-style diet.

Another genetic strain of mouse became obese on the Atkin’s diet and showed signs of metabolic syndrome but was healthier on the Western diet.

One of the researchers, Dr William Barrington, of North Carolina State University, said: “There is an overgeneralization of health benefits or risks tied to certain diets.

“Our study showed that the impact of the diet is likely dependent on the genetic composition of the individual eating the diet, meaning that different individuals have different optimal diets.

“We've largely viewed diet the same way for the last 100 years – assuming that there is one optimal diet.

“Now that we've identified that this is likely not the case, I think that in the future we will be able to identify the genetic factors involved in the varying responses to diet and use those to predict diet response in humans.”

The study found there were different reasons why the different kinds of mice gained weight.

“Some mice on specific diets simply ate more calories, and this caused them to become obese. However, mice on other diets ate less but still became obese,” Dr Barrington said.

The Atkin’s-style diet caused all the different strains of mice to burn more calories without an increase in activity, the researchers found, but some of them on this diet ate too much food and became obese.

Dr Barrington, who presented the findings at the Allied Genetics Conference, a meeting hosted by the Genetics Society of America, said: “Given the metabolic and genetic similarity of humans and mice, it is highly likely that the level of diversity of diet response seen in our study will also be observed in humans.

“Since there are different optimal diets for different individuals, this underscores the need for precision nutrition, which would identify optimal dietary patterns for each person.”

He said that mice were “a powerful model” for studying the effects of different diets on different genetic make-ups “because they have similar susceptibilities to obesity and metabolic syndrome, and we can model the genetic diversity that is seen in humans while controlling for environmental factors”.