Having a high fat diet in your twenties and thirties makes you more likely to have heart disease and diabetes later

A high-fat diet in your twenties and thirties increases the risk of poor health later – not just because of weight gain.

According to researchers at Qingdao University in China, fatty foods cause a reduction and mutation of so-called "good" bacteria in the intestine.

Specifically, an unhealthy diet modifies microbiomes – which break down foods in the stomach – and causes an increase in inflammatory markers throughout the body.

The data, published online in the journal Gut, raise fears that it will sow the seeds of metabolic disorders, such as diabetes, heart disease and stroke, in the long run.

Researchers investigated whether different levels of dietary fat are altering intestinal bacteria in healthy young adults from China.

In Asia, eating habits are changing from low in fat and high in carbohydrates to relatively high in fat and carbohydrates.

Researchers divided 217 healthy people between the ages of 18 and 35 and had normal weight in three dietary groups.

Participants then received different ratios of carbohydrate – white rice and wheat – and fat – mainly soybean oil.

The intake of fiber and protein remained the same in all participants.

The three basic diets were either low in fat, fat making up 20% of the participants' energy intake.

Moderate fat – equal to 30% of energy intake – or high in fat – lipids accounting for 40% of energy intake.

Each participant followed his diet for six months.

Its impact on intestinal bacteria and inflammatory markers was assessed in blood and stool samples taken at the beginning and at the end of the experiment.

After six months, participants in all three groups lost weight, those who followed the low-fat diet lost the most.

However, some changes that may have long-term health implications are only apparent in the high-fat samples.

Although there have been no major changes in the overall volume of intestinal bacteria among the three groups, the number of beneficial bacteria producing short-chain fatty acids, including butyrate, does not occur. only increased in the group of low fat diets.

In contrast, the number of these beneficial bacteria decreased in the high-fat group.

And the number of "bad" bacteria in the bowels of people with type 2 diabetes, for example, had increased.

Some bacteria, such as Blautia species – associated with lower cholesterol levels – were abundant among those on a low-fat diet.

Bacteroides species, associated with high cholesterol levels, were more common in people with a high fat diet.

In addition, the high-fat diet was associated with significant and potentially harmful changes in long-chain fatty acid metabolism.

This has resulted in higher levels of chemicals that can cause inflammation.

The opposite was true for the low fat diet.

The researchers pointed out that sampling was only done at the beginning and end of the trial.

And a more complete picture of microbial changes would have emerged with more frequent sampling.

As all three groups lost weight, it is also unclear whether weight loss was the cause of the changes, or vice versa.

And since the participants were all young, healthy and of normal weight, the results may not be more widely applicable, they add.

But the results seem to illustrate the need to reduce dietary fat, suggest the scientists.

"Compared to a low-fat diet, long-term consumption of a high-fat diet seems to be undesirable …. a higher fat content," they concluded.

Their conclusions could also have consequences for other countries.

"These results could also be relevant in developed countries where fat intake is already high," the researchers added.