New research by German scientists reveals that those who want to start a diet should begin with a fast. According to the study, fasting helps people lose weight and normalize their metabolism and blood pressure. It can also reverse metabolic syndrome, a cluster of conditions that increase heart disease risk, strokes, and diabetes.

Many people around the world suffer from metabolic syndrome, otherwise known as insulin resistance syndrome. In Germany alone, one in four people has metabolic syndrome. This condition is an umbrella term for four major co-occurring conditions: obesity, high blood pressure, lipid metabolism disorder, and diabetes. All of these conditions increase the risk for severe cardiovascular events like heart attacks and strokes.

What the study found

Doctors have found that lifestyle changes such as diet, exercise, and fasting have proven effective against metabolic syndrome. Patients may still need to take medication to stabilize markers of health. Doctors normally tell patients to start a diet by adopting a low-calorie eating program. However, they still don’t fully understand how nutrition affects the microbiome, immune system, and overall health.

A study by German researchers investigated the effects of starting a diet on people with metabolic syndrome. Dr Sofia Forslund and Professor Dominik N. Müller led the group. Both are from the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC) and the Experimental and Clinical Research Center (ECRC).

“Switching to a healthy diet has a positive effect on blood pressure,” says Andras Maifeld, first author of the paper. “If the diet is preceded by a fast, this effect is intensified.” The study was recently published in the journal Nature Communications.

Start a diet with more vegetables and less meat.

Dr. Andreas Michalsen from Immanuel Hospital Berlin and Professor Gustav J. Dobos from the University of Duisburg-Essen recruited 71 volunteers. All of them had metabolic syndrome along with high blood pressure. The researchers then split them randomly into two groups.

Researchers put both groups on the DASH (Dietary Approach to Stop Hypertension) diet for three months. This diet specifically targets high blood pressure and is very similar to the Mediterranean diet. It includes an abundance of fruits and vegetables, grains, nuts, pulses, fish, and lean white meat. Researchers instructed one of the two groups to fast for five days before starting the DASH diet.

Using immunophenotyping, the scientists observed that the immune cells of volunteers in this group changed when they started the diet. “The innate immune system remains stable during the fast, whereas the adaptive immune system shuts down,” explains Maifeld. When this happens, the number of proinflammatory T cells decreases, and regulatory T cells populate.

Fasting along with a Mediterranean diet can boost health dramatically

Researchers then took stool samples to study how fasting impacted the gut microbiome. Gut bacteria can either impair or boost the immune system, depending on the strains present. For instance, some types of bacteria metabolize dietary fiber into short-chain fatty acids that lower inflammation and boost immunity.

The German research team found that the gut microbiome changed dramatically when patients started a diet and fasted. Healthy bacteria that aid in reducing blood pressure began multiplying. They noticed that even after patients began eating after the fast, some of the positive changes remained.

In particular, “Body mass index, blood pressure and the need for antihypertensive medication remained lower in the long term among volunteers who started the healthy diet with a five-day fast,” explains Dominik Müller. Normally, a patient’s blood pressure will rise when they forget to take even one antihypertensive pill.

The volunteers had lower blood pressure even three months after the fast.

The German researchers and scientists from the Helmholtz Centre for Infection Research and McGill University, Montreal, Canada, analyzed these results. They performed a statistical evaluation of the data using artificial intelligence to rule out medications to improve health. The team wanted to confirm that the positive results came from patients adopting a healthier lifestyle. They utilized methods from a prior study to investigate the effects of antihypertensive medicine on gut bacteria.

“We were able to isolate the influence of the medication and observe that whether someone responds well to a change of diet or not depends on the individual immune response and the gut microbiome,” says Forslund.

Sometimes, people who start a diet of high-fiber, low-fat foods don’t see results. In most cases, they don’t have the gut bacteria to metabolize fiber into protective fatty acids.

“Those who have this problem often feel that it is not worth the effort and go back to their old habits,” explains the scientist.

However, starting a diet fast can change the gut bacteria, making it easier to break down fiber. “Fasting acts as a catalyst for protective microorganisms in the gut. Health clearly improves very quickly, and patients can cut back on their medication or even often stop taking tablets altogether.” Seeing results relatively quickly could encourage patients to keep eating healthy in the long term as well.

This study shows that those who want to start a diet may benefit from fasting first. Even a short fast can “reset” the gut and increase metabolism, making it easier to lose weight.

start a diet
Final Thoughts: German researchers prove that fasting is a healthy way to start a diet

Many people have preconceived notions about fasting, perhaps believing it could damage your health. However, the German research team discovered that undergoing a fast and adopting a Mediterranean-style diet can drastically improve health. The group that fasted for five days before beginning the diet had fewer pro-inflammatory immune cells and more regulatory T cells. This means that their health had improved during the fast, even before they started the DASH diet.

If you have wanted to start a diet, consider fasting first to kickstart your results. This study shows that fasting helps reset gut bacteria, promoting weight loss, lower blood pressure, and improved metabolism. Fasting for short periods is not dangerous and can start a diet on the right note.