Intermittent fasting may make you lose muscle, not fat: Other side effects you cannot ignore

A new study found that intermittent fasting resulted in very modest weight loss, but two-thirds of the lost pounds came from lean mass.

By: Longjam Dineshwori | | Updated: October 2, 2020 9:24 am

Loss of lean mass in intermittent fasting may result from lack of protein or physical activity. © Shutterstock

A diet regimen that has become popular in recent years is intermittent fasting. It is an eating pattern that specifies when you should eat, rather than what you should eat. Intermittent fasting also referred to as time-restricted eating is all about switching between fasting and eating on a regular schedule. It is increasingly gaining popularity as a diet option for weight loss. Some research even claimed that intermittent fasting can increase weight loss by boosting fat burning and metabolism. However, a new study has refuted these claims. Also Read - Is it safe to do intermittent fasting while breastfeeding?

The randomized clinical trial, which is said to be one of the most rigorous studies on intermittent fasting to date, tracked 116 obese and overweight individuals over three months to see if the eating pattern lives up to the hype. Also Read - Intermittent fasting is not for everyone: Should you choose this eating plan?

In terms of weight loss, the team didn’t find any significant difference between time-restricted eating and simply eating three meals a day. Instead, they discovered an unintended side effect of intermittent fasting: the loss of lean muscle. Also Read - Intermittent fasting for weight loss: How to make time-restricted eating sustainable

The study was recently published in the journal JAMA Internal Medicine.

Intermittent fasting did not offer any other metabolic advantage

In the study, half of the participants practiced daily time-restricted eating — eating all their meals between noon and 8:00 p.m. then fasting for 16 hours. The other half followed the normal three meals a day eating, including snacks. Over three months, researchers tracked both group’s weight and metabolic outcomes, but there was no greater weight loss with time-restricted eating compared with the consistent meal group.

They also didn’t see any significant differences in fat mass, fasting insulin, blood sugar, HbA1C, or blood lipids between the two groups.

Over the course of the study, the fasting participants lost about three and a half pounds. But more than fat they were losing lean mass, including muscle. The researchers found that two-thirds of weight loss came from lean mass. This is not a good sign because one should be losing fat mass, not muscle.

One potential factor for loss of lean mass is that fasting participants weren’t eating enough protein or getting enough physical activity, the researchers explained.

Other side effects of intermittent fasting

Here are some other side effects that this eating pattern is likely to cause.

Loss of appetite

Studies have suggested that intermittent fasting may reduce appetite over time. While this may help with weight loss, you’re also likely to suffer from nutritional deficiencies, fatigue, headache, and lack of energy.

Disturbed sleep

If you take your dinner at 7 pm or 8 pm, it is quite likely to feel hungry at 11 pm or 12 at midnight and your sleep may be disturbed.

Slow metabolism

Long fasting periods and lack of sufficient nutrition can slow down your body’s metabolism. Therefore, people with diabetes, those with a history of eating disorders like anorexia and bulimia, and pregnant or breastfeeding women are advised to avoid that this kind of diet plan.

Too much reliance on caffeine

Some health experts recommend drinking tea or coffee during the fasting period of intermittent fasting. Over a period of time, too much reliance on coffee may become an inevitable side effect of intermittent fasting.

Published : October 1, 2020 8:02 pm | Updated:October 2, 2020 9:24 am

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