US reveals long-term impact of junk food diet, exercise on kids

The analysis showed that the gut bacteria are sensitive to the amount of exercise the mice got

A recent study has shown that a high-fat, high-sugar diet had lasting effects on the microbiome of mice, and the same may be true for humans. The study by UC Riverside researchers is one of the first to show a significant decrease in the total number and diversity of gut bacteria in mature mice fed an unhealthy diet as juveniles.

“We studied mice, but the effect we observed is equivalent to kids having a Western diet, high in fat and sugar and their gut microbiome still being affected up to six years after puberty,” explained UCR evolutionary physiologist Theodore Garland. 

The microbiome refers to all the bacteria as well as fungi, parasites, and viruses that live on and inside a human or animal. In this study, Garland’s team looked for impacts on the microbiome after dividing their mice into four groups: half fed the standard, ‘healthy’ diet, half-fed the less healthy ‘Western’ diet, half with access to a running wheel for exercise, and half without. 

After three weeks spent on these diets, all mice were returned to a standard diet and no exercise, which is normally how mice are kept in a laboratory. At the 14-week mark, the team examined the diversity and abundance of bacteria in the animals.

They found that the number of bacteria such as the Muribaculum intestine was significantly reduced in the Western diet group. This type of bacteria is involved in carbohydrate metabolism. 

The analysis also showed that the gut bacteria are sensitive to the amount of exercise the mice got. Muribaculum bacteria increased in mice fed a standard diet who had access to a running wheel and decreased in mice on a high-fat diet whether they had exercise or not.