Changes in body weight, adherence, and appetite during 2 years of calorie restriction: the CALERIE 2 randomized clinical trial

Authors: DORLING, JAMES - Pennington Biomedical Research Center; DAS, SAI KRUPA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; RACETTE, SUSAN - Washington University School Of Medicine; APOLZAN, JOHN - Pennington Biomedical Research Center; ZHANG, DACHUAN - Pennington Biomedical Research Center; PIEPER, CARL - Duke University Medical Center; MARTIN, CORBY - Pennington Biomedical Research Center

Submitted to: European Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2020
Publication Date: 3/6/2020
Citation: Dorling, J.L., Das, S., Racette, S.B., Apolzan, J.W., Zhang, D., Pieper, C.F., Martin, C.K. 2020. Changes in body weight, adherence, and appetite during 2 years of calorie restriction: the CALERIE 2 randomized clinical trial . European Journal of Clinical Nutrition. 74:1210-1220. https://doi.org/10.1038/s41430-020-0593-8.
DOI: https://doi.org/10.1038/s41430-020-0593-8

Interpretive Summary: In humans, calorie restriction (CR), defined as a reduction in caloric intake while maintaining nutrition, has been linked with lower risk of chronic disease, such as heart disease and diabetes, and lower risk of age-related comorbidities, or the presence of two or more medical conditions at the same time. The Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE) study showed that individuals without obesity achieved significant (~ 12% over the two year period) CR and lost 10% body weight over two years. However, time-course changes in adherence, weight, and appetite during the CALERIE study had not been examined. To investigate changes in these factors over time, we analyzed the data from 143 CALERIE participants who were randomly assigned to consume 25% less energy than they were consuming at the start of the study. Our findings show that adherence to CR dipped below its target at approximately month six; weight loss occurred until approximately one-year and then plateaued. Self-reported hunger and thirst were not significantly increased. Our findings suggest that in individuals without obesity, a 25% CR program can lead to meaningful weight loss and promote aging-related benefits, with acceptable levels of adherence and no adverse effects on appetite.

Technical Abstract: Background/objectives The Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE) study showed that individuals who are nonobese were able to undergo significant calorie restriction (CR), yet the time course changes in adherence, weight, and appetite are unknown. This analysis aimed to investigate the time course changes in adherence, body weight, and appetite during the CALERIE study. Subjects/methods Overall, 143 participants (body mass index: 21.9-28.0 kg/m2) were randomized to a CR group that aimed to achieve 25% CR for 2 years. Throughout the intervention, body weight was measured, and appetite was assessed through visual analogue scales. Algorithms were utilized with body weight measurements to calculate adherence percentile score. Participants targeted an adherence percentile score of 50, though being between 80 (lowest acceptable adherence) and 10 (highest acceptable adherence) was adequate. Polynomial regression analyses were used to assess time course changes. Results Polynomials indicated that adherence percentile score increased above 50 after approximately week 20, although adherence remained acceptable (adherence percentile score less than 80) (R2=0.89; P<0.001). Weight loss occurred until approximately week 60 and then plateaued (R2>/= 0.92; P<0.001). Hunger and thirst increased (R2 >/= 0.30; P< 0.001), but the total increase in scale scores were <10mm throughout the intervention. Conclusions In individuals who are nonobese, adherence to 25% CR declines after 20 weeks, but 2 years of CR that stimulates a meaningful reduction in weight, promotes aging-related benefits and negligibly affects appetite is viable.