Fasting before beginning a healthy diet may kick-start weight loss and lower blood pressure, study finds

Fasting before beginning a healthy diet may kick-start weight loss and lower blood pressure, study finds
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  • Starting a healthy diet may have even more benefits if it begins with a fast, a new study found.
  • Fasting can help improve the number of beneficial bacteria in the gut, according to researchers.
  • If you're fasting for health reasons, always consult an expert to avoid side effects and risks.

Kicking off a new diet regimen with a period of fasting could increase the health benefits, according to a study published March 30 in Nature Communications.

Researchers from the Max Delbruck Center for Molecular Medicine in Berlin looked at 71 volunteers with metabolic syndrome and high blood pressure as they embarked on a three month diet. All the participants followed the DASH diet, designed to improve blood pressure by focusing on produce, whole grains, and lean meats. Half the group started their diet with a five day fasting period of no solid food.

The researchers found that while participants did benefit from the diet, the fasting group saw more positive results for their body weight and blood pressure than their non-fasting peers.

The positive effects of fasting were maintained even at the end of the three month diet.

"Switching to a healthy diet has a positive effect on blood pressure," Andras Maifeld, first author of the study and a researcher at the Experimental and Clinical Research Center in Berlin, said in a press release. "If the diet is preceded by a fast, this effect is intensified."


Fasting may improve the gut microbiome

The study found that fasting dramatically changed the gut microbiome, the bacteria that live in the digestive system. Beneficial types of bacteria, associated with lower blood pressure, multiplied during the fast, the researchers found.

"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," Sofia Forslund, lead co-author of the study and scientist at the Max Delbrück Center for Molecular Medicine, said in the press release.

Those positive changes appeared to persist even after the study participants resumed eating, which could explain why they saw more improvements than the group who didn't fast.

Consult a medical expert before fasting to avoid serious side effects

If done improperly, however, fasting can backfire for metabolism and overall health and well-being.

While shorter forms of intermittent fasting are generally regarded as safe for most people, it isn't for everyone. And fasting for more than a day at a time can be risky, potentially causing fatigue, dizziness, blood pressure fluctuations, loss of muscle mass, and immune system disruption.


Seek the advice of a qualified professional before taking on a serious fasting regimen or multi-day fast.