Metabolism

At baseline, older adults exhibited reduced expression of genes associated with cellular respiration and energy metabolism compared to young adults with comparable activity levels.

After hitting a plateau around the age of 20, the data suggest that our metabolisms don’t really start to decline until after age 60. The slowdown is gradual, only 0.7% a year. But a person in their 90s needs 26% fewer calories each day than someone in midlife.