Contrary to popular opinion that lean individuals "eat what they want" and exercise more, Hu et al. study a cohort of healthy underweight volunteers and reveal them to have reduced physical activity relative to normal BMI controls and lower food intake. This cohort is also shown to have higher than expected resting energy expenditure, which is associated with elevations in thyroid hormones.
Funded by the National Key R&D Program of China (2019YFA0801900) and the National Natural Science Foundation of China (31570409 and 91731303 to J.R.S. and 31900831 to S.H.). We thank all the volunteers for devoting their time to this study.
Data Availability StatementSupplemental Information
Supplemental information can be found online at https://doi.org/10.1016/j.cmet.2022.05.012.