Nutritional quality of calorie restricted diets in the CALERIE 1 trial

Authors: RACETTE, SUSAN - Washington University School Of Medicine; GARR BARRY, VALENE - Washington University School Of Medicine; BALES, CONNIE - Duke University School Of Medicine; MCCRORY, MEGAN - Boston University; OBERT, KATHLEEN - Washington University School Of Medicine; GILHOOLY, CHERYL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; ROBERTS, SUSAN - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; MARTIN, CORBY - Pennington Biomedical Research Center; CHAMPAGNE, CATHERINE - Pennington Biomedical Research Center; DAS, SAI KRUPA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Experimental Gerontology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2022
Publication Date: 8/1/2022
Citation: Racette, S.B., Garr Barry, V., Bales, C.W., Mccrory, M.A., Obert, K.A., Gilhooly, C., Roberts, S., Martin, C.K., Champagne, C., Das, S. 2022. Nutritional quality of calorie restricted diets in the CALERIE 1 trial. Experimental Gerontology. https://doi.org/10.1016/j.exger.2022.111840.
DOI: https://doi.org/10.1016/j.exger.2022.111840

Interpretive Summary: This study analyzes the nutritional quality of self-selected diets of individuals in 6- to 12-month trials of calorie restriction. The trial was designed to determine the feasibility of calorie restriction in adults without obesity. The analysis found that nutritional adequacy and diet quality generally were higher during calorie restriction relative to baseline. The findings suggest that moderate calorie restriction does not compromise nutrient intake in adults without obesity.

Technical Abstract: Objectives: The aim was to determine the nutritional adequacy of calorie restricted (CR) diets during CR interventions up to 12 months. Methods: The Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE) phase 1 trial consisted of 3 single-site studies to test the feasibility and effectiveness of CR in adults without obesity. After baseline assessments, participants who were randomized to a CR intervention received education and training from registered dietitians on how to follow a healthful CR diet. Food diaries were completed at baseline and during the CR interventions (~6, 9, and 12 months) whenp articipants were self-selecting CR diets. Diaries were analyzed for energy, macronutrients, fiber, 11 vitamins, and 9 minerals. Nutritional adequacy was defined by sex- and age-specific Estimated Average Requirement (EAR) or Adequate Intake (AI) criteria for each nutrient. Diet quality was evaluated using the PANDiet diet quality index. Results: Eighty-eight CR participants (67% women, age 40 +/- 9 y, BMI 27.7 +/- 1.5 kg/m2) were included in the analysis. Dietary intake of fiber and most vitamins and minerals increased during CR. More than 90% of participants achieved 100% of EAR or AI during CR for 2 of 4 macronutrients (carbohydrate and protein), 6 of 11 vitamins (A, B1, B2, B3, B6, B12), and 6 of 9 minerals assessed (copper, iron, phosphorus, selenium, sodium, zinc). Nutrients for which < 90% of participants achieved adequacy included fiber, omega-3 fatty acids, vitamins B5, B9, C, E, and K, and the minerals calcium, magnesium, and potassium. The PANDiet diet quality index improved from 72.9 +/- 6.0% at baseline to 75.7 +/- 5.2% during CR (p < 0.0001). Conclusion: Long-term, calorie-restricted diets were nutritionally equal or superior to baseline ad libitum diets among adults without obesity. Our results support modest calorie restriction as a safe strategy to promote healthy aging without compromising nutritional adequacy or diet quality.