You're Into the Wrong Foods

Unhealthy eating is the biggest driver of big bellies. Too many starchy carbohydrates and bad fats are a recipe for that midsection to expand. Instead, get plenty of veggies, choose lean proteins, and stay away from fats from red meats. Choose healthier fats in things like fish, nuts, and avocados.

Even a moderate cutback on carbs (grains, pasta, sugars) can help, too.

You're Just Too Into Food

That under-skin belly fat (called subcutaneous) and the fat under your abdominal muscles and around vital organs (called visceral) need to go. Visceral fat makes cardiovascular disease and diabetes more likely. It can also lead to high blood pressure and more. Eating too much is at least partly to blame for that flab. Limiting your portions can keep visceral fat down.

You're Smoking

We all know the dangers of smoking. Add this to the list: One study showed that it leads to more abdominal and visceral fat. So if you needed one more reason to quit, you have one.

You're Stressed

When the stress hormone cortisol goes through your body, fat takes residence in your belly. Talk to your doctor about how to handle your stress. Exercise can help ease it. Meditate. Do yoga. Put together a good support system. Talk to a mental health professional if you need it.

You're Not Exercising Enough

Nobody said shedding belly fat was going to be easy. If your gut is stretching the tape measure too much -- for men, that's more than 40 inches around the waist, and women, more than 35 -- you need moderate physical activity (like walking) for at least 150 minutes a week, or vigorous (running) for 75, and strength training at least twice a week. Check with your doctor first before starting any exercise program.

You're Doing the Wrong Exercises

Those sit-ups aren't enough. You also need weight training to build muscle. More muscle means more calorie burning.

That said, if you can only do one exercise, choose aerobic exercise (like walking or running). It works best for burning fat. Make it a habit, and slowly ratchet up the intensity to get the results you're after.

You Like Beer

It's not just beer and the carbs in beer that make that beer belly pop. All alcohol has calories. If you take in too many calories -- especially if you're not exercising and eating well -- you're going to pack on the pounds. If you drink, remember to do it in moderation.

Sports and Energy Drinks Fill Your Fridge

Sports drinks can have a lot of sugar. That brings calories. If you drink too many of these, you're setting yourself up for weight gain that might end up around your beltline. Cut back on sugary, high-calorie drinks. That means energy drinks and non-diet sodas, too.

You're Not Drinking Enough Water

Studies show that drinking more water can help you lose weight. Choosing H2O instead of sweetened drinks means fewer calories. That can help you trim that belly fat. It's also the only beverage that can hydrate without adding sugars or other compounds.

Genetics

Yes, your family tree affects your chances of obesity. It also has a say in where you store fat. Still, there is hope. Striking the right balance between how many calories you take in (your diet) and how many you burn (through exercise) can help keep you from gaining weight, despite your genes.

You're Not Sleeping Well

Those nighttime raids on the fridge are diet killers. Not only that, if you're not sleeping, you're jump-starting stress hormones. Those encourage your body to keep fat.

Learn good sleep-time habits, like:

• Put down the phone.
• Turn off the laptop.
• Go to bed at the same time each night.
• Avoid alcohol before bed.
• Get your exercise.

You're Obsessed With the Scale

Here's some good news: You might be losing that belly fat and not even realize it. If you're eating well and exercising right, remember that how your clothes fit -- measured by your waist size -- is more important than what the scale says. If that waistband is less snug, you may have replaced some belly fat with muscle.