Genetics and Diet

This month we are looking at the effects of genes on weight and other aspects of health and whether there are any diets or dietary rules that are worth following. There are many dietary regimes to choose from but do they really work and how can you know which is best for you? Here you can read about the latest research into whether our genes affect our response to what we eat and their effect on weight gain. Then we’ll investigate whether it’s worth going low carb or low fat.

Genetics and Diet

The chances are you know someone who has transformed their health and body shape by following a particular dietary regime, whether it’s paleo, vegan, low carb or low fat. But there is very little agreement, even among experts who study food and diet, as to which is the best diet. This may be because there simply isn’t one diet that suits all people at all times.

This could also be one of the reasons why much of the broad spectrum dietary advice given out by governments and health agencies is so ineffective, as proven by the epidemic of obesity and other diet related diseases in the Western world.

Do Genes Make a Difference?

Part of the difference in response to different diets appears to be genetics. In order to test the effects that genetic differences have on dietary responses researchers used 4 different groups of animal models to test 5 diets over a 6 month period. The genetic differences within each group were negligible whilst the genetic differences between groups translated to roughly the same as between two unrelated people.

The diets used were:

• The American style diet high in fat and refined carbs.
• The Mediterranean diet including wheat and red wine extract.
• The Japanese diet including rice and green tea extract.
• The ketogenic diet or Atkins style diet which is high in fat and very low in carbs.
• The control group ate a diet of standard chow.

The diets were matched for fibre content and bioactive compounds to make them as similar to human diets as possible. The quantity of food was unlimited.

Which Diet Worked Best?

American Diet

None of the groups did well on the American diet. 2 of the groups became very obese with signs of metabolic syndrome.

Mediterranean Diet

The Mediterranean diet worked well for most individuals although some experienced a small amount of weight gain.

Japanese Diet

Although the Japanese diet worked well for most individuals one of the 4 genetic types did poorly on this diet, even to the extent of experiencing fatty liver or liver damage. This same group did well on the other diets.

Atkins Diet

2 of the genetic types did well on the Atkins like diet while the other 2 did very badly. One group became obese with fatty livers and high cholesterol. The other had a reduction in activity levels and gained more body fat despite remaining lean. This is equivalent to humans who appear to be a healthy weight but actually have a high percentage of body fat.

One Diet Does Not Suit All

These results demonstrated that the same diet can make one set of individuals lean while causing weight gain and health problems in others. The researchers say that one day they would like to develop a genetic test that could tell each person which diet would suit their genetic make up.

However, that test isn’t here yet and there may be more factors than genetics at play. For more information read the blog posts on Low Fat or Low Carb Diets? Which is Best? and 6 Foods to Avoid.

References

1. Barrington WT, Wulfridge P et al. Improving Metabolic Health Through Precision Dietetics in Mice. Genetics, 2017; genetics.300536.2017