Why metabolism slows after 60

Spoiler alert: you're so efficient at staying alive

As we age, metabolism doesn’t just ‘slow down,’ it shifts. And when it comes to resting energy expenditure (REE), those shifts can have real consequences, especially in older adults. REE is the baseline energy we burn just staying alive: breathing, circulating blood, keeping our organs functioning (Rawson et al., 2023). But the way our body burns that energy changes in predictable ways across the lifespan.

According to Pontzer et al. (2021), REE stays surprisingly stable from our 20s through our 50s, once body size and composition are accounted for. After 60, it starts to decline around 0.7% per year. That drop is not just about losing muscle, it reflects a slowdown in the metabolism of key organs like the brain, liver, and heart. These high-energy tissues become less metabolically active with age, so even if an older adult’s weight stays the same, their energy needs do not.

If you’ve hit a point where “what used to work” no longer does—especially around energy, appetite, or weight—it m…