Practiced before a diet, fasting would improve its effects

About one in five French people has a metabolic syndrome. Otherwise known as syndrome X, it refers to the coexistence of several health problems associated with excess weight. These metabolic disorders increase the risk of type 2 diabetes, heart disease and stroke. To normalize lipid and carbohydrate metabolism, where most metabolic disorders originate, weight loss is one of the most effective treatments. In a study presented on March 30 in the journal NatureCommunicationsGerman researchers suggest that fasting before a diet for weight loss acts as an eating catalyst in people with metabolic syndrome.

A Mediterranean diet is good…

The researchers looked at the effect of a change in diet on people with metabolic syndrome and wanted to analyze whether combining fasting with this diet can increase its effects. “Switching to a healthy diet has a positive effect on blood pressuresaid Andras Maifeld, lead author of the paper. If the diet is preceded by a fast, this effect is intensified.” To reach these conclusions, he and his team of researchers recruited 71 volunteers with metabolic syndrome and high systolic blood pressure. They were randomly divided into two groups. Both followed the DASH (Dietary Approach to Stop Hypertension) diet – designed to combat high blood pressure – for three months, but the second group observed a five-day fast before starting the diet. This Mediterranean-style diet includes lots of fruits and vegetables, whole foods, nuts and legumes, fish, and lean white meat.

Scientists first observed that the change in diet, which switched to a diet designed to fight hypertension, is beneficial. They also saw how it materializes in the body. “The innate immune system remained stable during fasting, while the adaptive immune system shut downthe researchers found. During this process, the number of pro-inflammatory T cells decreases, while regulatory T cells multiply.”

…but fasting makes it better

Using stool samples, the researchers examined the effects of fasting on the gut microbiome. These effects are important since intestinal bacteria work in close contact with the immune system. For example, certain strains of bacteria metabolize dietary fiber into anti-inflammatory fatty acids that are beneficial to the immune system. With fasting, the composition of intestinal bacteria changes dramatically and bacteria that reduce blood pressure multiply. Researchers have observed that some of these changes persist even after food intake is resumed. “Body mass index, blood pressure, and need for antihypertensive drugs remained lower over the long term in volunteers who started a healthy diet with a five-day fast”, advances Dominik Müller who co-directed the team of researchers.

To go further, the researchers conducted a statistical evaluation of these results using artificial intelligence to ensure that this positive effect is indeed attributable to the fast and not to the drugs taken by the volunteers. For this, they joined forces with German scientists from the Helmholtz Center for Infection Research and Canadians from McGill University in Montreal. “We were able to isolate the influence of the drug and observe that whether or not a person reacts to a change in diet depends on the individual immune response and the gut microbiome.”, continues Sofia Forslund, who co-led the team of researchers.

If a high-fiber, low-fat diet isn’t working, it may be because there aren’t enough gut bacteria in the gut microbiome that metabolize fiber into protective fatty acids. “Those who have this problem often feel that it is not worth it and go back to their old habits.”, adds the researcher. Combining fasting would make up for this lack. “Fasting acts as a catalyst for protective microorganisms in the gut. Health clearly improves very quickly and patients can reduce their medication intake or often even stop taking tablets altogether and this could motivate them to adopt a healthy lifestyle in the long term”, she concludes.

Fasting can prevent proper muscle development

Several studies have also pointed to limited effects of intermittent fasting for weight loss. A study published on September 28 in the JAMA even suggested that it prevents proper muscle development. “Any way you look at it, intermittent eating resulted in very modest weight loss.” said Ethan Weiss, co-author of the study. He adds : “Intermittent fasting offered no other metabolic benefit. Moreover, the loss of lean mass is a worrying signal.”