Evidence for protein leverage on Total Energy Intake, but not Body Mass Index, in a large cohort of older adults

BACKGROUND Protein leverage (PL), the phenomenon of food consuming until absolute intake of protein meets a target value, regardless of shortfall or overconsuming for other nutrients in the diet and total energy intake (TEI). Evidence for PL was observed in humans, recently in a cohort of youth with obesity. This study aimed to test for PL and the protein leverage hypothesis (PLH) in a cohort of older adults. METHODS We conducted a retrospective analysis of dietary intake in a cohort of 1699 community-dwelling older adults aged 67-84 years from the NuAge cohort. We computed TEI and the energy contribution (EC) from each macronutrient. The strength of leverage of macronutrients was assessed through power functions ( TEI = µ * EC L ). Body mass index (BMI) was calculated, and mixture models were fitted to predict TEI and BMI from macronutrient ECs. RESULTS The mean TEI was 7,673 kJ and macronutrient ECs were 50.4 %, 33.2 % and 16.4 %, respectively for carbohydrates, fat, and protein. High carbohydrate intake was associated with low fat intake. There was a strong negative association ( L = -0.37; p < 0.001) between the protein EC and TEI. Each percent of energy intake from protein reduced TEI by 77 kJ on average, ceteris paribus . BMI was unassociated with TEI in this cohort, so the PLH could not be tested here. CONCLUSIONS Findings: indicate clear evidence for PL on TEI, but not on BMI, likely because TEI and BMI become increasingly uncoupled during aging.