It's not a secret that a fat diet promotes weight gain.

But can grapefruit juice neutralize the consequences of malnutrition?.

It turns out that.

At least, the researchers from the University of California at Berkeley. In their experiments on mice grapefruit juice against a very fat and high-calorie diet not only slowed down weight gain, but also increased insulin sensitivity.

A team of scientists led by Joseph Napoli and Andreas Stahl from the University of Dietetics and Toxicology published this week's results on the pages of PLOS ONE.

Grapefruit has been offered for weight loss since the 1930s, and today it is part of the famous Hollywood diet. Studies show that the grapefruit contains an enzyme that burns fats and promotes rapid weight loss.

But Napoli and Stahl say that the credibility of these studies is questionable. They state that until today no adequate tests have been performed on people who could confirm the effect of grapefruit on metabolism and its ability to "burn fat".

In their new work, scientists decided to test the metabolic effects of grapefruit juice.

Grapefruit juice slows down weight gain and reduces sugar levels in mice.

The researchers tested purified grapefruit juice diluted with water in different proportions in five groups of mice that received low or high fat food for 100 days. Grapefruit juice for rodents was sweetened with saccharin.

These groups were compared to the control group, which was fed with fatty food, but instead of grapefruit juice, water was given. Scientists added glucose and artificial sweeteners to water, so the calorie content of water was the same as that of sweetened grapefruit juice in other groups.

At the end of the study, scientists found that mice that received fatty foods and drank grapefruit juice gained 18% less weight compared to their relatives who drank sweet water. Moreover, in these mice the blood sugar level was 13-17% lower than in the control group, and the level of insulin was 3 times lower - insulin sensitivity increased significantly!.

Grapefruit juice had no effect on the body weight of mice that received nourishment with a low fat content, but even they had reduced insulin levels by a factor of 2 compared to the control group.

Then the team tested the effects of the active substance grapefruit - naringin - on one group of mice with a fatty diet. Naringin, which athletes use as food additives for burning fat, was previously associated with weight loss. Another group of mice with a fatty diet at this time received metformin - a common sugar-reducing drug.

It turned out that naringin reduces the level of sugar in the blood as effectively as metformin. But after all, metformin is an approved and well studied drug, and naringin is a little-studied flavonoid, which is used in the form of dietary supplements only by enthusiasts.

"In fact, this means that natural fruit juice can act as well as an approved prescription drug," says Napoli.

Scientists write that naringin itself does not affect the body mass gain in mice with a fatty diet. This suggests that for weight loss is responsible for some other active component of grapefruit.

"Grapefruit juice contains many active ingredients, and we do not always understand how they work," Stahl said..

Why does grapefruit juice work only with a fat diet?.

Scientists are not yet able to explain why grapefruit juice delays body weight gain.

They write that all laboratory mice had the same physical load and caloric intake, so this fact requires an explanation. In their opinion, it can not be explained by a change in the absorption of nutrients in the digestive tract, because scientists controlled the composition of excrement of mice.

"In fact, we could not find any obvious reasons that would explain the effect of grapefruit juice on weight gain. But something we are going to check in the course of future research, "says Stahl.

The study of Napoli and Stahl was funded by the California Grapefruit Co-operative. Scientists emphasize that the sponsors did not exert any influence on the control and results of the study.

As explained in the cooperative, their interest in research of this kind is due to the fact that grapefruit is a natural treasure, possessing a mass of useful properties. They just need to open up and tell the society about it, and research needs money.

By the way, the benefits of grapefruit are not limited to weight control. In 2012, the MNT reported that grapefruit juice can increase the effectiveness of the anti-cancer drug sirolimus (sirolimus). Another study suggested that grapefruit prevents the formation of kidney cysts.

medbe. en.