5 Science-Backed Reasons Why Weight Gain Is A Problem As You Age

Weight gain after 40

One unfortunate reality is most people gain weight with age and if you aren’t strength training, most of that weight gain is body fat. How much weight do most people put on? According to the U.S. Department of Health and Human Services, during the decade between ages 30 and 40, men gain around 15 pounds while women put on about 7 pounds. But the weight gain doesn’t stop there. For women, weight gain speeds up after menopause because of hormonal changes and lack of physical activity.

Age-related weight gain is a frustrating problem that has real health consequences. The worst kind of fat is visceral fat, deep belly fat that deposits deep in the abdominal cavity and causes an increase in waist size. Research links gains in visceral fat with many health problems, including cardiovascular disease and type 2 diabetes.

By now, you’re probably wondering why people gain weight with age and whether it’s preventable. Let’s look at what science shows about weight gain, aging, and what causes it.

Loss of Muscle Mass

Both men and women begin to lose muscle mass after the age of 30. The only way to reduce muscle loss is to work your muscles against resistance through strength training. How does loss of muscle lead to weight gain? As you lose muscle, your resting metabolic rate modestly slows, meaning you burn fewer calories at rest. Plus, muscle increases insulin sensitivity and that makes it easier for your body to burn fat rather than store it. Plus, you need muscle strength and mass to stay functional too.

Medications & Weight Gain

Medications are another reason people put on weight. As people grow older, they’re more likely to take one or more prescriptions, and a surprising number of medications make it easier to gain weight. Some prescription and non-prescription medications that cause weight gain include diabetes medications, antidepressants, antihistamines, corticosteroids, seizure medications, and some drugs that lower blood pressure.

People often don’t think about medications being a cause of weight gain but it’s common. You may not notice a rise in weight when you first take them. It may show up after you’ve been taking the medication for a while. Check with your physician and see if you’re taking prescriptions that make it harder to control your weight.

A Busy Lifestyle

Life becomes more complicated with age. If you’re middle-aged or older, you probably aren’t as active as you were in your 20s. You have a family to take care of and a job that takes up a lot of time. Plus, you have less time to cook healthy meals and are more likely to grab something on the go. Changes in lifestyle habits play a major role in whether you gain weight. Poor quality sleep and chronic stress also make it harder to slim down.

How can you avoid the pitfalls of a busy schedule? Start making small, sustainable lifestyle changes. Cook one time weekly and make enough healthy food to last the whole week. Exercise as soon as you wake up in the morning before other obligations get in the way. Small changes add up over time to big health benefits.

Hormonal Changes & Weight Gain

Where people store weight shifts in middle age and after menopause in women. There’s a tendency to store fat in the belly and around the waist. This type of fat, called visceral fat, is the most unhealthy type since it increases the risk of health problems, like type 2 diabetes and cardiovascular disease.

The best way to tackle visceral fat is to start an exercise program and include some high-intensity exercise in your workouts. Studies show that vigorous exercise is most effective for reducing visceral fat. Cut back or eliminate sugar and refined carbohydrates too. They are another contributor to visceral fat gains.

One hormonal change that can lead to weight gain is an underactive thyroid gland. When your thyroid gland doesn’t produce as much thyroid hormone, your resting metabolic rate slows, and you’ll gain weight. Hypothyroidism, an underactive thyroid, is more common in women and often shows up during or after menopause. All it takes is a simple blood test to check thyroid function and rule this condition out as a cause of pesky weight gain.

The Way Your Body Processed Fat Changes

A study published in Nature Medicine adds new insight into why people gain weight as they age. This study shows lipid turnover within fat cells slows with aging. The rate at which cells remove fat slows, increasing the likelihood of gaining body fat. Fortunately, scientists believe there’s something you can do about changes in fat turnover. They believe exercise helps prevent weight gain related to sluggish fat turnover. Exercise can improve your body composition too if you do both weight training and aerobic exercise.

The Bottom Line

Now you know why the pounds creep up on you over the years. It doesn’t happen all at once but adding even a pound per year can lead to an unhealthy body weight after a few decades if you never lose the pounds you gain. There still isn’t a quick and easy treatment for weight gain due to aging. However, eating a healthy diet low in sugar and refined carbohydrates combined with exercise, adequate sleep, and stress management will help you control your weight as you age.

Research reveals exercise helps reduce gains in body fat related to aging. However, a study showed maintaining the same exercise program at the same intensity over time isn’t enough to prevent a gradual rise in body weight. You need to increase the intensity of your workouts to avoid weight gain. If you exercise at a moderate intensity, add high-intensity interval training to the mix. Strength training is essential too since it helps maintain lean muscle mass. So, don’t exercise less as you get older, exercise with more intensity!



  • S. News and World Report. “Why It’s Harder to Lose Weight as You Age”
  • University of Rochester Medical Center. “When Your Weight Gain Is Caused by Medicine”
  • Arner, S. Bernard, L. Appelsved, K.-Y. Fu, D. P. Andersson, M. Salehpour, A. Thorell, M. Rydén, K. L. Spalding. Adipose lipid turnover and long-term changes in body weight. Nature Medicine, 2019; 25 (9): 1385 DOI: 10.1038/s41591-019-0565-5.
  • Int J Obes (Lond). 2006 Mar; 30(3): 543–551. doi: 10.1038/sj.ijo.0803172.


Related Articles By Cathe:

5 Ways Psychological Stress Leads to Weight Gain

6 Surprising Reasons You Gain Weight in the Winter

How Meditation Can Help You with Weight Training

How Mindfulness Meditation Can Help You with Weight Training

How Lack of Quality Sleep Limits Muscle Growth

Hi, I'm Cathe

I want to help you get in the best shape of your life and stay healthy with my workout videos and Free Weekly Newsletter. Here are three ways you can watch and work out to my exercise videos:

Get Your Free Weekly Cathe Friedrich Newsletter

Get free weekly tips on Fitness, Health, Weight Loss and Nutrition delivered directly to your email inbox. Plus get Special Cathe Product Offers and learn about What’s New at Cathe Dot Com.

Enter your email address below to start receiving my free weekly updates. Don’t worry…I guarantee 100% privacy. Your information will not be shared and you can easily unsubscribe whenever you like. Our Privacy Policy