Tue. Oct 26th, 2021

USC researchers find that interrupting a low-fat, high-calorie diet with regular cycles of a fasting diet helps mice

Regular cycles of a fasting-like diet improved the health and longevity of mice that otherwise ate a high-fat diet. Credit: Jonathan Haase / University of Southern California

In a new USC study of the health effects of a low-calorie diet that mimics fasting in the body, the researchers found that regular five-day cycles of the diet in mice seemed to counteract the harmful effects of their usual low-calorie, high-calorie diet. The study, published today in Metabolism in nature, analyzed the diet, health, and longevity of three different groups of mice over two years.

The results point to the potential of using a fasting-like diet as “medicine,” according to the researchers. A fasting mimic diet, or FMD, is a low-calorie diet that “lures” the body into a fasting state.

A group of mice ate a high-calorie, low-fat diet (with 60% of their calories from fat) and became unhealthy and overweight. Another group of mice ate the same poor diet as the first for about 4 weeks followed by five days where they were fed an MKS and two days with a normal, healthy diet.

Study authors say these short diet interventions were sufficient for the second group to return to normal levels of cholesterol, blood pressure, and weight. The mice that ate the fasting mimic diet for five days out of each month lived as long as a third group of mice that were consistently fed a healthy diet.

In humans, obesity caused by a low-fat and low-calorie diet is a major risk factor for metabolic syndrome, diabetes and cardiovascular disease.

“The study indicates that it is possible for mice to eat a relatively poor diet equivalent to a five-day fasting imitation diet,” said senior author Valter Longo, director of the Longevity Institute at USC Leonard Davis School of Gerontology and professor of biological sciences at USC Dornsife College of Letters, Arts and Sciences. “Our great discovery is that intervening with this diet made their hearts more resilient and better functioning than the mice that ate only a low-fat, low-calorie diet.”

The study authors say that cycles of FMD appeared to prevent obesity in mice by reducing the accumulation of visceral and subcutaneous fat – all without causing loss of body mass. FMD cycles also seemed to improve heart function and prevent high blood sugar and high cholesterol.

According to researchers, the effect of FMD cycles on gene expression indicated a role in the conversion of fat cells to the prevention of obesity. Specifically, the impact of diet on fat accumulation and heart aging may explain protection against premature death caused by a low-fat and low-calorie diet.

The researchers warn that these results should not be misinterpreted. They stress that they do not recommend that people eat a diet high in calories and fat that is reduced by periodic fasting.

However, they say that the potential benefits of counteracting poor eating habits in this way should be further explored in clinical trials. These strategies can provide potential health benefits for people who may not be willing or able to change their diet every day.

The most effective diets for preventing or alleviating obesity in humans, including the ketogenic diet, often require radical and daily changes in dietary habits, the study authors say. These requirements result in very low long-term compliance.

Longo said the study may indicate a “sweet spot” for FMD in mice at five days a month.

“Even after the mice in the experimental group went back to their high-fat, high-calorie diet, the improved fat breakdown in their bodies continued for a fairly long period of time,” Longo explained. “Is there a similar sweet spot for humans where you can intervene for a few days and still keep breaking down fat for several weeks?

Early FMD trials indicate potential health benefits for humans, he added. Several clinical studies published by Longo and colleagues indicate that a monthly FMD caused fat loss without loss of muscle mass and improved cardiometabolic risk factors, especially in overweight or obese people. They say this new mouse study shows that these monthly FMD cycles can actually restore normal heart and metabolic health and longevity in animals fed a low-fat, high-calorie diet, a lifelong study that cannot be performed in humans.

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More information:
Amrendra Mishra et al., Fasting mimic diet prevents low fat diet effect on cardiometabolic risk and longevity, Metabolism in nature (2021). DOI: 10.1038 / s42255-021-00469-6

Provided by the University of Southern California

Citation: Discontinuation of low-fat, high-calorie diet with regular ‘fast’ cycles helps mice live longer, healthier lives: study (2021, October 14) retrieved October 14, 2021 from https://medicalxpress.com/news/2021- 10- low-fat-calorie-regular-fasting.html

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