You're Eating Too Much
If you take in more calories than you burn off, you put on pounds everywhere -- including in your middle. You need to cut about 500 calories a day to lose a pound. That may sound like a lot, but look at cutting the highest-calorie foods from your diet first. Cookies, French fries, soda, and juice pack many calories into a few sips or bites. Replace those first with low-calorie, nutrient-dense foods like broccoli, apples, brown rice, and brothy soups.
You've Had a Few More Birthdays
Age might bring wisdom, but it isn't kind to your midline. With each passing year, your muscle mass declines, and your metabolism slows, so you don't burn as many calories as you used to. That means you can eat the same amount and still see the number on the scale creep up. Age-acquired weight tends to collect around the middle. To prevent unwanted gains, cut back on calories or add more muscle-building exercise.
Blame Your Genes
If you eat right and exercise and those stubborn pounds still won't go, your genes could be to blame. Another clue is if other family members struggle with their weight. Genes control how your body burns calories, how quickly you feel full, and whether you gain weight in your thighs, butt, or belly. Even if belly fat runs in your family, you can overcome your genes with the right diet and enough exercise.
You've Started ‘The Change’
In women, the combination of aging and the loss of estrogen at menopause adds up to weight gain. Genes, loss of muscle mass, and overeating also contribute to weight creep in your 40s and 50s. The extra pounds that might have settled in your hips earlier in life now cluster in your middle, also thanks to hormone changes. That weight shift does more than make your pants tighter. It can also raise your risk for heart disease.
You Don't Move Enough
Americans spend more than 10 hours a day in a seated position. Although diet plays a major part in weight gain, lack of movement contributes, too. To avoid putting on extra pounds in your belly and elsewhere in your body, get at least 150 minutes of moderate-intensity or 75 minutes of high-intensity aerobic exercise each week.
Sleep Is Hard to Come By
Too little shut-eye could be part of the reason you've gained weight. Your body makes hormones that make you feel full. Lack of slumber can make them less effective. That’s why, when you’re sleep-deprived, you may overeat and gain weight, especially in your belly. When you don’t get enough sleep, you may also crave more high-calorie comfort foods.
You're Stress Eating
Too much stress isn't good for your mental state or your weight. Stress triggers the release of cortisol, a hormone that makes you crave high-fat, carb-heavy foods like pizza, fries, and cookies. Cortisol also deposits fat around your belly. Another way stress leads to weight gain is by keeping you up at night. People who sleep fewer hours tend to have more belly fat.
You Haven't Kicked the Habit
Some people who smoke are afraid to quit because they worry that they’ll gain weight. But even though smokers have a lower body mass index than nonsmokers, their bellies are bigger. Smokers gain more visceral fat, the kind that's linked to heart disease and other chronic health conditions, than nonsmokers. So, in case you needed another reason to quit, now you’ve got one.
You Eat Too Many Trans Fats
These artificial fats raise bad (LDL) cholesterol and boost your risk for heart disease and type 2 diabetes. Foods cooked in trans fats are high in fat and calories and can cause weight gain. The FDA has banned added trans fats in foods, but some products made before the ban could still be on store shelves. Read food labels. If the ingredients list includes partially hydrogenated vegetable oil, that food contains trans fat. Try to choose a different item.
Your Gut Bacteria Aren't Helpful
Your intestines are home to trillions of bacteria. Some of these germs live in harmony with you and help your body digest food. Others break down food so much that your body absorbs more calories from it and stores more energy in the form of fat. There's evidence that probiotics, found in fermented foods like kimchi and yogurt, might get rid of belly fat. These friendly bacteria won't replace calorie cutting, but they might help.
It's Your Medicine
The answer to your weight gain could be hidden inside your medicine cabinet. Certain drugs are notorious for causing weight gain. These include some diabetes drugs, some antidepressants, steroids, and epilepsy medicines. A few medications add fat directly to the belly area, including beta-blockers, which treat high blood pressure.