You can think of burning calories as “Step 1 of being alive”, said Herman Pontzer, a professor of evolutionary anthropology at Duke University. Food gives your body the fuel it needs to stay healthy, he said.
Your age – among several other factors – can have a big effect on how many calories you need to maintain your body’s weight and basic functions, Dr Pontzer and other experts said.
Here’s what to know.
HOW YOUR AGE AFFECTS THE CALORIES YOU BURN
The size of your body is the most important factor that affects your calorie requirements, Dr Pontzer said. “The bigger you are, the more calories you need.”
But your life stage is also crucial, he added.
Babies and children, for example, require fewer calories than adults simply because they are smaller. But when you calculate how many calories they use relative to their body size, it’s actually more than what adults use because they are growing and developing, Dr Pontzer said.
Being more physically active also increases the number of calories you burn, said Anna Maria Siega-Riz, a nutrition professor and the dean of the School of Public Health and Health Sciences at the University of Massachusetts Amherst. She was the lead author of a 2023 report from the National Academies of Sciences, Engineering and Medicine that estimated the calorie needs of people in the United States and Canada.
According to that report, an inactive, 90.7kg, 40-year-old man would need about 2,700 calories per day to maintain his weight and basic bodily functions. But if he were an athlete training for a couple of hours each day, he would need about 3,500 calories per day.