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Why metabolism slows as you age

Do you feel like you gain five pounds after eating a slice of cake, when you could eat an entire cake in your 20s and never gain an ounce? It’s not your imagination. As we age, our metabolism slows and the rate at which we break down food decreases by 10 percent each decade after age 20.

Metabolism is the amount of energy (calories) your body uses to maintain itself. The number of calories your body burns when it’s at rest is determined by your basal metabolic rate (BMR) as well as how much you exercise and your muscle-to-fat ratio.

“By the time we’re 50, there’s a 30 percent drop,” says Karen Andry, a licensed and registered dietitian and bariatric coordinator at Piedmont Atlanta Hospital

Why it’s so easy to gain weight

A slowing metabolism can lead to weight gain each year even if you don’t eat much more than usual.

For example, if you eat a bowl of ice cream every night – about 500 calories – you will have consumed 3,500 extra calories that week, which amounts to a pound of fat. Multiply this by 52 weeks a year and you can see a significant weight gain from consuming just one extra treat a night.

“It’s very simple to gain the weight, but it’s very difficult to take it off,” says Andry. 

Maintaining muscle mass is the key to preventing weight gain, but it can be challenging because after age 45, the average person loses an estimated 1 percent of muscle mass each year. Click here to find strengthening exercises for the whole body.

Maintaining a healthy weight takes effort, so be mindful of what you eat every day and increase your physical activity.

Ideal body weight

How do you know if you are at your ideal weight? Medical staff typically either determine your body mass index score or use a simple formula like this one:

  • Female – 5’0” = 100 lbs
  • Female – 5’1” = 105 lbs
  • Female – 5’2” = 110 lbs
  • Female – 5’3” = 115 lbs.
  • Female – 5’4” = 120 lbs.
  • Female – 5’5” = 125 lbs.

“We use the Metropolitan Life Insurance tables for ideal body weight from years ago,” says Andry. “They’re not really very realistic; however, they’re used across the board so you can compare apples to apples.”

Because weight is so unique to each person’s lifestyle and risk factors, your best course of action is to talk with your primary care physician to determine your personal weight target.  Click here to find a doctor near you.

For more fitness and nutrition tips, visit the Living Better Health & Wellness page

Need to make an appointment with a Piedmont physician? Save time, book online.

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