What Really Changes About Metabolism After 40

The story that metabolism collapses at 40 is more dramatic than the reality. What changes most is muscle mass, activity level and sleep — and each of those is something you can influence.

Muscle does most of the work

Less muscle means fewer calories burned at rest. Strength work and steady protein intake protect it.

Daily movement counts

Walking, stairs and standing add up to more than most structured workouts do in a week.

Where keto fits

Lower-carb eating helps many women feel steadier and less hungry, which makes the protein and movement pieces far easier to keep up.