Does metabolism really slow down with age?

On Ep. 315, Maggie says studies show metabolism barely budges from about age 20 to 64. On Ep. 306, dietitian Abbey Sharp says the data shows it stays relatively consistent until about 70. On Ep. 371, JJ Virgin says the idea that metabolism slows with age doesn't really hold up. Her point is that what's changing is your muscle.

Nikkiey explains on Ep. 398 that without resistance training you lose roughly 3% to 8% of your muscle every decade after 30. Muscle drives your metabolism, so every pound you lose means your body burns fewer calories at rest. By the late 40s or early 50s, without consistent lifting, metabolism can be significantly slower, and she says that isn't age. On Ep. 303 she ties it to years of under-eating, especially protein. Maggie adds that muscle and bone are both metabolically active, so losing them leaves less of a glucose sink and extra energy gets stored as fat.

There is nuance. JJ Virgin says falling estrogen, rising insulin resistance, higher cortisol and poorer sleep can make you better at storing fat, particularly around the midsection. Abbey Sharp says fat distribution shifts with estrogen and the body needs more support at this stage, not necessarily less food. On the older Ep. 75, Nikkiey says the body does burn somewhat fewer calories at rest, but the big reason is that people slow down, becoming more sedentary at work and at home. If you have questions about your own hormones, those are worth taking to your doctor.