Is it true that metabolism decreases with age?
That’s a question I get asked quite frequently.
Do you notice that last year’s clothes are tight on you or that the number on the scale reads higher than it used to?
Whether that happens because of a decrease in metabolism or sloppy nutrition and decreased physical activity, it seems true that with each passing year, most people gain weight.
We hear a lot about childhood obesity numbers increasing. However, the adult rates are alarming as well. In the U.S. 35 percent of adults are obese and over 67 percent overweight or obese.
Some research suggests that susceptibility to permanent weight gain seems to be highest during adolescence, pregnancy, and midlife for women and the period after marriage for men. For most, the weight gain doesn’t end in middle age. Researchers say this is due to an “energy imbalance.”
The concept of energy imbalance is easy to understand: eat more calories than you burn and you will gain weight. Eat fewer and you will lose weight. With 3500 calories in a pound of fat, it doesn’t take much to put on a pound or two per year. It could be as little as a two extra sodas every month or a few too many neglected 20-minute evening walks.
But what is metabolism’s role in age-related weight gain?
It turns out that for most people, age-related weight gain is due in large part to a dramatic decrease in calories burned. While lower levels of physical activity play a large role in the decreased energy expenditure, an age-related decline in metabolic rate is also to blame.
A study evaluating total energy expenditure (TEE), which includes your metabolism, plus the energy required to digest and absorb food, and physical activity, confirmed what most people already know: energy expenditure decreases with age.
Basal metabolic rate, which accounts for about 50 to 70 percent of TEE, is thought to decrease about one to two percent per decade. That is, after a person reaches 20 years old, daily energy expenditure decreases about 150 calories per decade. The decline is probably due to decreased muscle mass (which is highly metabolically-active) and increased fat mass (which is relatively metabolically-inactive).
This decline seems to be most rapid after age 40 in men and 50 in women.
To sum it up,, the number of calories burned per day decreases with age. This reality is widely accepted and is even built in to formulas that estimate resting energy expenditure.
BUT, and this is a BIG BUT, while a small decrease in daily energy expenditure is probably inevitable, with a committed fitness program, “aging” adults (anyone over 20 years old) can avoid sizeable decreases in metabolic rate.
So what’s the key to fighting age-related weight gain and a declining metabolic rate???
Incorporating these elements into a committed fitness program!
- Strength training and muscle building to maintain metabolically active muscle mass.
- Cardiovascular physical activity to maintain a high level of energy expenditure and prevent increased fat mass.
That’s why I focus on those topics in so many of these blog posts!