Alpha Femme Keto The younger, the easier to lose weight, because the resting energy expenditure is higher. Once growth ceases, it decreases approximately 5% per decade, and after 50 years it does so by 10% or so. ” One of the reasons, says the Mayo Clinic, is that at a higher age, lower muscle mass, which translates into a considerable reduction in resting energy expenditure. And there is another fundamental fact: the TB represents between 60 and 70% of a person's total energy expenditure.