Intermittent Fasting Increases Belly Fat

Weight Loss From Lean Body Mass and Muscle

Intermittent fasting, often referred to time-restricted eating, has become the latest diet craze not only for weight loss but also for enhancing health. Everyone from well-known celebrities to everyday, average people are trying intermittent fasting and claiming it is successful.

In a study on intermittent fasting published in the prestigious journal JAMA Internal Medicine on September 28, 2020, researchers questioned, “What is the effect of time-restricted eating on weight loss and metabolic health in patients with overweight and obesity?” The researchers’ findings acknowledge, “In this prospective randomized clinical trial that included 116 adults with overweight or obesity, time-restricted eating was associated with a modest decrease (1.17%) in weight that was not significantly different from the decrease in the control group (0.75%).” Meaning that during the three-month study on a daily 16-hour-fast (eating all their meals between noon and 8:00 pm), participants only lost 2 to 3 pounds, slightly better than their control group. The most concerning finding of the study was that 65 percent of weight loss from the fasting group was not fat, but from lean body mass and muscle. A healthy weight loss comes from a diet that enhances body fat loss, not muscle and lean body mass. Having more muscle increases metabolism and helps you burn more calories over a 24-hour period.

A new published study in the March 2, 2021 Journal Cell Reports concluded that every-other-day fasting makes it more difficult to lose belly fat and deep visceral abdominal fat. Increasing abdominal fat is strongly linked to increased incidence of type 2 diabetes and cardiovascular disease.

This new study was done in mice and not humans, because their physiology is similar but mice have a much faster metabolism. This is important because it allowed the researchers to use advanced instrumentation, examining tissues and measuring changes carefully and more precisely in the body much more easily.

The results of the study found that when mice fasted and went into starving or “preservation mode,” the mice stored more abdominal visceral and subcutaneous fat rather than burning it for energy! This type of metabolic adaptation may make intermittent fasting a less desirable diet for weight loss and for optimal health! Even though the study was done using mice, the researchers feel similar effects are most likely to occur in humans and that intermittent fasting is ineffective for burning belly fat – and they acknowledge that the other diets may be found to be more effective and successful.

For the fourth consecutive year, U.S. News & World Report ranked the Mediterranean diet as the #1 Best Overall Diet. The article says, “Research suggests that the diet can ward off chronic diseases and improve longevity.” The Mediterranean Diet was also tied as #1 for the easiest diet to follow: the best diet for diabetes; best heart-healthy diet, and best plant-based diet too. These results were based on a panel of 23 experts, and 41 diets based the scientific literature. The expert panel consisted of the country’s top nutrition experts and physicians specializing in weight loss, diabetes, and cardiovascular disease. I have been an advocate of the Mediterranean diet for over 25 years.

A breakthrough, long-term diet study was published in the American Heart Association journal Circulation on measuring abdominal and body fat! This diet study used magnetic resonance imaging (MRI) technology for the first time, measuring changes in body and organ fat during 18 months on a Mediterranean/low-carb diet, with and without moderate physical exercise. MRI is a diagnostic technique that produces computerized images of organs and internal body tissues using a magnetic field and radio waves. This is the best approach to date for measuring body fat, compared to weighing people as a result of diet and exercise. The scale, skinfold calipers or underwater weighing are not giving you the whole picture!

The aforementioned research was conducted between Ben-Gurion University of the Negev and Harvard University; the research group was led by Drs. Iris Shai, Yftach Gepner, Ilan Shelaf and Dan Schwarzfuchs from Ben-Gurion University. Dr. Meir Stampfer was also a lead author for the study, and is from the prestigious Harvard University. Dr. Stampfer is a well-known authority on nutrition and obesity. The study analyzed the implementation of positive dietary changes and how this could help in reducing body fat, particularly visceral (abdominal) body fat.

The Mediterranean low-carb diet was significantly superior to low-fat diet in decreasing fat storage, including visceral (deep abdominal) liver and heart fat. High visceral fat has been shown to increase metabolic syndrome, inflammation, cardiovascular disease and diabetes. Losing deep subcutaneous visceral fat, as well as haptic (liver) fat, was associated with improved insulin sensitivity and improved lipid profile.

The low-carb Mediterranean diet was more effective than a low-fat diet in eliminating fat storage, especially abdominal fat! Previous studies have shown that a low-carb Mediterranean diet may be an effective alternative to low-fat diets. It has a more favorable effect on lipids (with low-carb diet) and glycemic control (with Mediterranean diet).

In a groundbreaking, two-year dietary intervention study published in the New England Journal of Medicine, researchers found that the Mediterranean and low-carb diet was an effective alternative to weight loss. It appears to be just as safe, metabolically healthier and more effective compared to a low-fat diet. Consumption of monounsaturated fats (extra-virgin olive oil and nuts) is thought to improve insulin sensitivity, which may explain the favorable effect on blood glucose and insulin levels. Research has shown that nut consumption can enhance weight loss and weight gain (N Engl J Med, 2008).

People who strictly follow the Mediterranean diet tend to have a lower body mass index (BMI), which is a measure of the proportion of weight to height and waist circumference – according to a large population study led by Simona Bertoli from the Nutritional Research Center in Milan, Italy. The Mediterranean diet is high in fish, seafood, antioxidant-rich vegetables, red wine and berries rich in polyphenols, beans, lentils, nuts, legumes and extra-virgin-olive oil (EVOO) that are rich in healthy monounsaturated and polyunsaturated fats and low in saturated fats. Extra-virgin olive contains a polyphenol called oleuropein and can increase brown fat thermogenesis.

Brown fat is a special kind of fat cell that generates heat and helps regulate bodyweight and energy expenditure. The body has two forms of fat – white fat and brown fat. Brown fat burns calories. The more brown fat you have, the more calories you burn. The capability of harnessing one’s one brown fat for fat burning is revolutionary! The ability to get lean by producing extra brown fat and enhancing and activating existing brown fat represents a promising way to burn fat. Several landmark discoveries and approaches to this are being explored at major research centers and universities worldwide, with great excitement. Brown fat research is a hot topic today!

©Published by Advanced Research Media, Inc. 2021

©Reprinted with permission from Advanced Research Media, Inc.


1. Proteomics analysis of adipose depots after intermittent fasting reveals visceral fat preservation mechanisms. Dylan J. Harney, Michelle Cielesh, Renee Chu, Kristen C. Cooke, David E. James, Jacqueline Stöckli, Mark Larance. CELL REPORTS: 2 March 2021

2. Lowe DA, Wu N, Rohdin-Bibby L, Moore AH, Kelly N, Liu YE, Philip E, Vittinghoff E, Heymsfield SB, Olgin JE, Shepherd JA, Weiss EJ. Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Intern Med. 2020 Nov 1;180(11):1491-1499. doi: 10.1001/jamainternmed.2020.4153. PMID: 32986097; PMCID: PMC7522780.

3. U.S. News Reveals Best Diet Rankings for 2021. January 4, 2021. US News & World Report.

4. Olive oil may lower heart disease risk. American Heart Association News. March 5, 2020.

5. Olive Oil Consumption and Cardiovascular Risk in U.S. Adults. Journal of the American College of Cardiology. Marta Guasch-Ferré, Gang Liu, Yanping Li, Laura Sampson, JoAnn E. Manson, Jordi Salas-Salvadó, Miguel A.

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