Persistence of weight loss and acquired behaviors 2 y after stopping a 2-y calorie restriction intervention

Abstract

Background: Calorie restriction (CR) influences aging processes and extends average and maximal life spans. The CALERIE 2 (Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy Phase 2) study was the first randomized clinical trial to examine the metabolic and psychological effects of CR in nonobese humans.Objective: We conducted a 2-y follow-up study of adults who underwent 2 y of CR or ad libitum (control) consumption and determined whether weight loss and acquired behaviors persisted after the study ended when participants determined their own lifestyle behaviors.Design: In this prospective, longitudinal study, we assessed differences in weight, body composition, psychological function, and energy expenditure in 39 nonobese [body mass index (in kg/m2): 22-28] men and women (25% CR: n = 24; control: n = 15) 12 and 24 mo after they completed the CALERIE 2 study at Pennington Biomedical.Results: Of 39 participants who were in the follow-up study, 29 subjects (CR: n = 18; control: n = 11) completed all visits at follow-up months 12 and 24. After the CR intervention, a mean ± SEM weight loss of 9.0 ± 0.6 kg was observed in the CR group, in which only 54% of the weight was regained 2 y later. Despite such a regain, weight, the percentage of body fat, and fat mass remained significantly reduced from baseline throughout follow-up and remained significantly less than in the control group (P < 0.05). At follow-up, the CR group retained higher degrees of dietary restraint and avoidance of certain foods.Conclusion: After a 2-y intensive CR intervention, ∼50% of CR-induced weight loss was maintained 2 y later, which was probably the result of lasting effects on acquired behaviors and dietary restraint. This trial was registered at clinicaltrials.gov as NCT00943215.

Keywords: CALERIE study; calorie restriction; diet; energy expenditure; metabolic adaptation; mood; quality of life; weight loss.

© 2017 American Society for Nutrition.

Figures

FIGURE 1

CALERIE 2 follow-up Consolidated Standards of Reporting Trial diagram. Participant throughput from enrollment (n = 39) to data analysis (n = 29). Analyses were performed on 29 men and women who on the basis of objective criterion (weight change) were determined to be adherent to their assigned treatment groups during the intervention. CALERIE 2, Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy Phase 2; CR, calorie restriction; FU12, follow-up at 12 mo; FU24, follow-up at 24 mo; M24, month 24 of the 2-y intervention.

FIGURE 2

Mean ± SEM weight achieved throughout the intervention and follow-up of control participants (n = 11) and CR participants (n = 18) who were determined to be adherent during the intervention and completed the follow-up study in full. Two-sample t tests of least-squares means ± SEMs were used from mixed-model repeated measures. A significant weight change from baseline existed between groups at all visits (P < 0.05). *Significant within-group weight change from baseline, P < 0.05. CR, calorie restriction; FU12, follow-up at 12 mo; FU24, follow-up at 24 mo; M0, month 0 of the 2-y intervention (baseline); M12, month 12 of the 2-y intervention; M24, month 24 of the 2-y intervention.

FIGURE 3

Mean ± SEM behavioral changes throughout the intervention and follow-up. A comparison is shown of behavioral changes in cognitive restraint (via the EI) and avoidance of forbidden foods (via the MAEDS) between the control group (n = 11) and CR group (n = 18) after M12 and M24 of CR followed by 12 and 24 mo of a self-selected diet. Data presented represent adjusted changes from baseline. Two-sample t tests of least-squares means ± SEMs from mixed-model repeated measures were used. *Significant within-group difference, P < 0.05. *Significant between-group difference, P < 0.05. ‡Significant treatment main effect for the MAEDS indicating that the mean change from baseline across the intervention and follow-up periods was higher in the CR group (CR group: 5.44 ± 1.13; control: −0.72 ± 1.45), P = 0.002. CR, calorie restriction; EI, Eating Inventory; FU12, follow-up at 12 mo; FU24, follow-up at 24 mo; MAEDS, Multifactorial Assessment of Eating Disorders Symptoms; M12, month 12 of the 2-y intervention; M24, month 24 of the 2-y intervention.