:

How many calories does a woman in her 40s burn a day? A guide to daily energy expenditure

By age 40, a woman's metabolism can slow by approximately 5% per decade, largely due to a natural loss of muscle mass. This can impact **how many calories does a woman in her 40s burn a day**, making a one-size-fits-all number difficult to pinpoint, and instead, requires a more personalized approach based on activity level, body composition, and other key factors.