Metabolism remains relatively stable from about age 20 to 60. It does not significantly slow down during this period. Research shows that metabolic rate starts to decline noticeably only after age 60, decreasing by approximately 0.7% per year thereafter
. The slowing of metabolism with age is linked to factors such as loss of muscle mass, hormonal changes, and reduced physical activity, which all contribute to a lower calorie burn rate at rest
. However, the metabolic rate itself remains "rock solid" through mid-life and only begins to decline gradually in later years
. In summary:
- Metabolism is stable from age 20 to 60.
- Metabolic rate starts to slow down after age 60.
- The decline is gradual, about 0.7% per year after 60.
This challenges the common belief that metabolism slows significantly starting at age 30 or 40
