Written by Joyce Smith, BS. Overweight or obese adults who participated in time-restricted eating (TRE) experienced a 1.17% modest weight loss that was very similar to the weight loss (0.75%) in the control group that practiced consistent meal timing (CMT).
There has been a dramatic increase in weight gain and obesity which has increased the risk for chronic diseases 1,2.Two lifestyle modifications have been considered as weight loss interventions. One is TRE, where eating ad libitum is permitted from 12:00 PM until 8:00 PM followed by complete abstinence of caloric intake from 8:00 PM until 12:00 PM the following day. Outside of this eating window, only zero-calorie beverages are allowed. In contrast, CMT involves eating 3 structured meals per day but allows for permissive snacking between meals. Studies have shown that TRE can prevent weight gain in mice who are on an isocaloric high-fat diet 3 and support weight loss and improve metabolic outcomes in already obese mice 4. TRE has also resulted in decreased caloric intake, body weight and fat mass in obese and overweight humans 5,6.
This randomized clinical trial 7 sought to determine whether obese and overweight individuals on an 8-hour TRE diet could lose weight and improve their metabolic markers compared to those who followed a CMT diet. One hundred and sixteen participants, ages 18-64 years, were randomized to 12 weeks of either a CMT diet or a TRE diet. The primary outcome was weight loss; secondary outcomes included changes in weight, fat mass, lean mass, fasting insulin, fasting glucose, hemoglobin A1c levels, estimated energy intake, total energy expenditure, and resting energy expenditure.
- At the end of twelve weeks, the TRE group experienced significant weight loss of 2.07 lbs. from baseline (0.94 kg, 95% CI -1.68 to -0.20 kg, P=0.01) while the CMT group lost a non- significant 1.5 lbs. (0.68 kg, 95% CI -1.41 to 0.05, P=0.07). Analysis revealed no significant difference in weight loss between the two groups (-0.26 kg [-0.57 lb.], 95% CI -1.30 to 0.78 kg, P=0.63).
- There were also no significant differences in secondary measures (changes in weight, fat mass, lean mass, fasting insulin, fasting glucose, hemoglobin A1c levels, estimated energy intake, total energy expenditure, and resting energy expenditure as well as no significant difference in the change in whole body fat mass between the two groups (-0.48 kg [-1.06 lbs], 99.7% CI -1.75 to 0.79 kg, P=0.30).
- There was, however, a decrease in lean mass (calculated as fat-free mass minus bone mineral content) only in the TRE group, and no between-group difference in the amount of lean mass after 12 weeks (-0.75 kg [-1.65 lbs], 99.7% CI -1.96 to 0.45 kg, P=0.09). However, appendicular (arms and legs) lean mass was greater in the TRE group and did differ significantly between the two groups (P =0.009) (TRE, P<0.001 vs CMT, P=0.16). Even markers of cardiovascular health (blood lipids, glucose, insulin and cardiometabolic markers including blood pressure) were similar between groups.
Self-reported adherence to the TRE diet was high probably because following it was less tedious and time-consuming, yet it yielded no greater weight loss. While these results are consistent with a prior study demonstrating that skipping breakfast has no effect on weight outcomes in patients trying to lose weight 8, it does contradict previous studies in which a TRE diet improved weight loss and other metabolic risk markers 6. Since the present study does not give credence to the TRE diet for weight loss and adds caution regarding the potential effects of TRE on appendicular lean mass, future studies that address the potential loss in appendicular lean mass as seen with the TRE diet are warranted.
Source: Lowe, Dylan A., Nancy Wu, Linnea Rohdin-Bibby, A. Holliston Moore, Nisa Kelly, Yong En Liu, Errol Philip et al. “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 180, no. 11 (2020): 1491-1499.
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Posted December 1, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Hales CM, Carroll MD, Fryar CD, Ogden CL. Prevalence of Obesity and Severe Obesity Among Adults: United States, 2017-2018. NCHS data brief. 2020(360):1-8.
- National Heart, Lung, and Blood Institute. Managing overweight and obesity in adults: Systematic evidence review from the Obesity Expert Panel. 2013.
- Hatori M, Vollmers C, Zarrinpar A, et al. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab. 2012;15(6):848-860.
- Chaix A, Zarrinpar A, Miu P, Panda S. Time-restricted feeding is a preventative and therapeutic intervention against diverse nutritional challenges. Cell Metab. 2014;20(6):991-1005.
- Antoni R, Robertson TM, Robertson MD, Johnston JD. A pilot feasibility study exploring the effects of a moderate time-restricted feeding intervention on energy intake, adiposity and metabolic physiology in free-living human subjects. Journal of Nutritional Science. 2018;7.
- Wilkinson MJ, Manoogian ENC, Zadourian A, et al. Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients with Metabolic Syndrome. Cell Metab. 2020;31(1):92-104.e105.
- Lowe DA, Wu N, Rohdin-Bibby L, et al. 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;180(11):1-9.
- Dhurandhar EJ, Dawson J, Alcorn A, et al. The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial. Am J Clin Nutr. 2014;100(2):507-513.
