Written by Steve Blechman
31 December 2021

 article 123121







By Steve Blechman


We all know that obesity is an independent risk factor from the coronavirus and severe illness. Now research has shown that just being overweight, not obese, can result in severe illness and even death! Intermittent fasting, often referred to as 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 it and claiming it is successful. Caloric restriction and intermittent fasting have been practiced for decades. It has gained popularity due to a growing body of research. Over the years, this research has shown that intermittent fasting and caloric restriction can enhance weight loss, cognitive function and help prevent heart disease, cancer and diabetes. It can also slow down the aging process and enhance longevity, but most of the research has been done on mice and rhesus monkeys, and not humans. A review and meta-analysis of intermittent fasting often referred to as time-restricted feeding (TRF) showed that it had a very positive effect on bodyweight and metabolism! But a commonly asked question remains: does intermittent fasting cause muscle loss? We will get more into the study below on the relationship between intermittent fasting, muscle loss and fat loss.


A new long-term study published in the December 2021 issue of the journal Medicine & Science in Sports & Exercise reported that a time-restricted eating program helped strength-training men lose weight, body fat and lower inflammation. Unfortunately, the strength-training participants lost muscle because their testosterone levels were lowered. The study was performed by researchers from institutions from Texas and Italy.


The study is very significant because it is the longest study of its kind on time-restricted eating. “The experiment was a single-blind, randomized study. Twenty healthy subjects were enrolled and underwent 12 months of either a time-restricted eating (TRE) diet or a normal diet (ND) protocol along with resistance training.” The subjects were young males in their 20s that had been weight training for at least five years prior to the study.


Antonio Paoli, MD who led the study said, “These findings demonstrated that well-trained resistance exercisers who would adhere to a fasting protocol for a long period of time can obtain beneficial effects on health biomarkers and inflammatory indices. Moreover, the long-term time-restricted eating approach spontaneously reduced the total caloric intake, driving a healthy weight loss. However long-term, time-restricted eating negatively effected muscle mass due to the significant negative impact reported on anabolic hormones in the population.”


A meta-analysis was published December 6, 2019, in the journal Reviews in Endocrine and Metabolic Disorders. The present systematic review and meta-analysis summarized the most recent evidence on the effect of time-restricted feeding (TRF) on weight loss and cardiometabolic variables in comparison with unrestricted time regimens. A total of 11 studies, 5 randomized controlled trials and 6 observational, were included. The findings of this important meta-analysis found greater weight loss with TRF than control regimens. There was also a significant reduction in fasting glucose and better blood sugar control in the TRF followers.


In a study 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 3 months 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% of weight loss from the fasting group was not fat but from lean body mass and muscle. A healthy weight loss is a diet that enhances body fat loss and not muscle and lean body mass. Having more muscle increases metabolism and helps you burn more calories over a 24-hour period. The researchers acknowledged that doing resistance training and eating more protein during the day may help prevent loss of muscle and lean body mass when practicing time-restricted fasting daily.


In conclusion, the recent and most significant study reported in the journal Medicine & Science in Sports & Exercise found that long-term intermittent fasting can cause severe muscle loss! Like I mentioned earlier, a healthy weight loss is a diet that enhances fat loss and not loss of lean body mass or muscle. Long-term intermittent fasting is not practical for bodybuilders or strength athletes who are striving to maximize their muscle mass.




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