Intermittent and continuous energy restriction result in similar weight loss, weight loss maintenance, and body composition changes in a 6 month randomized pilot study

Abstract

Summary Poor adherence is a barrier to successful weight control. Intermittent energy restriction (IER) provides an alternative approach to those for whom daily energy restriction is not ideal. This study assessed changes in weight, body composition, and macronutrient intake for an IER and a continuous energy restriction (CONT) approach within a multicomponent weight management intervention. We randomized 35 adults with overweight/obesity (BMI = 31.2 ± 2.4 kg/m2) to CONT or IER for 24 weeks (12‐week weight loss intervention and 12 weeks of weight loss maintenance). Diets were delivered within a multimodal weight management program including weekly group meetings with a registered dietitian, increased physical activity, and a comprehensive lifestyle change program. Retention and adherence were similar for CONT and IER. Weight, BMI, fat mass, percentage body fat, waist circumference, hip circumference, blood pressure, and heart rate all decreased after 24 weeks (all, P < .01), but there were no main effects of group (all, P > .27). Weight loss was clinically relevant in both CONT (11.38 ± 7.9%) and IER (9.37 ± 9.7%), and the proportion of each group achieving 5% weight loss was 82 and 61% (P = .16), respectively. Participant satisfaction was high in both groups. The results from this study (a) support the feasibility of IER as an alternative for weight loss and weight loss maintenance, (b) indicate that IER is an effective alternative to CONT for weight control and improvements in body composition, and (c) emphasize the importance of intensive lifestyle interventions with ongoing support for effective behaviour modification.

Updated Meta-Analysis of Studies from 2011 to 2021 Comparing the Effectiveness of Intermittent Energy Restriction and Continuous Energy Restriction

“…One study 13 from a previous report was added to the remaining 25 records. 14 - 38 Among the selected 26 articles, one trial with patients with type 1 diabetes mellitus 23 reported most of the targeted outcomes as medians and ranges without variances; therefore, we excluded it from our calculation of integrated mean differences (MDs) because of the unfeasibility of calculating the standard deviation (SD) from the given data. In the end, we included 16 RCTs from 25 articles comprising 1,438 participants in this meta-analysis ( Fig.…”

Comparison of the Effects of Intermittent Energy Restriction and Continuous Energy Restriction among Adults with Overweight or Obesity: An Overview of Systematic Reviews and Meta-Analyses

“…CER is a diet strategy of reducing 15–40% of the baseline calorie needs for a continuous period for weight loss [ 18 ]. Since the appearance of IER after CER, there has been increasing controversy about the effects of IER and CER among adults with overweight or obesity on weight loss, waist circumference, and body composition [ 19 , 20 , 21 ].…”

Is Intermittent Fasting Better Than Continuous Energy Restriction for Adults with Overweight and Obesity?

“…Irrespective of the duration of the intervention (short term [4-12 weeks] or long term [24-102 weeks]), weight loss with ADF and 5:2 fasting was comparable to that achieved by calorie restriction (CR). 10,14,15,[25][26][27][28][29][30][31][32][33][34] Meanwhile, weight loss with TRE alone (1%-5% decrease from baseline over 8-12 weeks) 23,35,36 was not superior to that achieved with CR and was less than that observed with ADF or 5:2 fasting unless total calorie intake was restricted along with TRE. Thus, long-term TRE combined with an appropriate energy-restricted diet can enhance weight loss, but this is mainly attributed to CR.…”