Intermittent Fasting: A fast trend

 As obesity rates continue to increase in the United States, leading to increased rates of cardiovascular disease, and other chronic diseases, new "trendy" diets continue to gain prominence as well. Paleo, keto, and intermittent fasting currently rule the media as the new ways to lose weight and look great. But as with all sensationalized things, they are usually based off of personal anecdotes and assumptions while continuing to confirm our theory that we truly know very little when it comes to nutrition.

In order to counteract that, a group in California decided to run the first randomized clinical trial to test the efficacy of intermittent fasting (IF), a form of time restricted eating (TRF). In TRF, the individual allows themselves only a window of time in a 24-hour window in which to eat their meals. In order to test the actual efficacy of this type of dieting, the group put together a sample of 141 participants who were considered overweight or obese at the time. The participants were randomized into the control group who were instructed to eat three structured meals a day based on consistent meal timing (CMT), and the experimental TRE group who were permitted to eat between 12:00-8:00pm everyday with 16 hours of fasting each for a three month period. The TRE group was only allowed non-caloric beverages in the fasting time frame, but were able to eat ad libitum during eating window. Of these groups, 92.1% self reported compliance in the CMT group, while 83.5% self reported compliance in the TRE group. Participants were given physical examinations to determine changes in weight, BMI, as well as other health biomarkers. 

At the conclusion of the study, researchers found that there was no significant difference in weight loss between the two groups, as well as no significant difference in changes to fat mass, glucose and insulin levels, or blood lipid levels. There was a significant difference however in reduction of lean muscle mass for the TRE group which exceeded 30% of the total weight loss reported. Prior studies had shown that TRE does prevent gains in lean muscle mass, but other factors are still unexplored. 

Due to the limited information on this type of dieting technique, there has been some opposition to the actual design of the study with arguments that the eating window should be narrowed more. The eating window should be earlier in the day, and that the participants should not have begun measurements until after three months in order to allow an adjustment period. This study has novelty as the first clinical trial to include a control group, but more research is need to truly determine the harms and benefits of TRE. 

The moral of this story is that just because one person has had success with a diet, does not mean it is suitable for everyone. It is likely that more is required including a healthier diet and increased metabolic output overall as opposed to following an easy new trend. 

Lowe, D.A., Wu, N., Bibby, L.R., Moore, H., Kelly, N., Liu, Y.E., Philip, E... Weiss, E.J. (2020). Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity. JAMA Internal Medicine, 180(11), 1491- 1499. https://doi.org/10.1001/jamainternmed.2020.4153