What is Metabolism?

Metabolism is the process the body uses to convert food into energy. Your body either uses this fuel right away or stores it in body tissues, like your liver, muscles or as body fat. Many factors influence metabolism including sex, age, thyroid levels, the ratio of muscle to fat and your emotional state.

Here are the answers to your biggest questions about metabolism after age 40, followed by simple ways to rev it back up again.

1. Why am I gaining fat in new places?

Answer: Mitochondria—the structures within cells that convert food into energy— slow down or die off after age 40. Subsequently, you can’t burn calories like you did before and can start gaining weight.

Solution: To combat the loss of mitochondria, cut 100 calories from your daily intake. Easy ways to trim 100 calories include removing skin from chicken breasts; using skim instead of whole milk in coffee; swapping mustard for mayo on sandwiches; and eating plain hamburgers rather than cheeseburgers. Studies show that eliminating 100 calories a day helps to keep weight off long term.

2. Why am I hungrier now than ever before?

Answer: After 40 your estrogen levels drop which causes insulin levels to go up and thyroid levels to go down, both of which increase hunger. You wind up eating more and burning fewer calories, which adds to the fat deep inside your belly known as omentum fat.