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Competing Interests: Funding Support and Author Disclosures The CIRCA-DOSE study was funded by a peer-reviewed grant from the Heart and Stroke Foundation of Canada (grant no. G-13-0003121), with additional financial support from Medtronic and Heart Rhythm Services at the University of British Columbia. The EARLY-AF study was funded by a peer-reviewed grant from the Cardiac Arrhythmia Network of Canada (grant no. SRG-15-P15-001), which is a Networks of Centres of Excellence program funded from a joint initiative of the Natural Sciences and Engineering Research Council, the Social Sciences and Humanities Research Council, the Canadian Institutes of Health Research, Industry Canada, and Health Canada. In addition, the trial was supported by unrestricted grants from Medtronic and Baylis Medical, as well as in-kind support from Medtronic (implantable cardiac monitors) and the University of British Columbia. Dr Khairy is supported by the André Chagnon research chair in electrophysiology and congenital heart disease. Dr Deyell has received grants from Biosense-Webster. Dr Macle has received personal fees from Medtronic; and grants and personal fees from St. Jude Medical/Abbott and Biosense-Webster. Dr Andrade has received grants and personal fees from Medtronic; grants from Baylis; and personal fees from Biosense-Webster. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: Protein leverage (PL) is the phenomenon of consuming food until absolute intake of protein approaches a 'target value', such that total energy intake (TEI) varies passively with the ratio of protein: non-protein energy (fat + carbohydrate) in the diet. The PL hypothesis (PLH) suggests that the dilution of protein in energy-dense foods, particularly those rich in carbohydrates and fats, combines with protein leverage to contribute to the global obesity epidemic. Evidence for PL has been reported in younger adults, children and adolescents. 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 macronutrients' ECs., Results: In this cohort of older adults, 53% of individuals had obesity and 1.5% had severe cases. The mean TEI was 7673 kJ and macronutrients' ECs were 50.4%, 33.2% and 16.4%, respectively for carbohydrates, fat, and protein. 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. However, BMI was unassociated with TEI in this cohort., Conclusions: Findings indicate clear evidence for PL on TEI, but not on BMI, likely because of aging, body composition, sarcopenia, or protein wasting., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)