Getting rid of your belly bulge is important for more than just vanity's sake. Excess abdominal fat—particularly visceral fat, the kind that surrounds your organs and puffs your stomach into a "beer gut"—is a predictor of heart disease, type 2 diabetes, insulin resistance, and some cancers. If diet and exercise haven't done much to reduce your pooch, then your hormones, your age, and other genetic factors may be the reason why reports Health.com.

Your workout isn't challenging enough

To banish stubborn belly fat, you have to ramp up your workouts. In a study published in the journalMedicine and Science in Sports and Exercise, people who completed a high-intensity workout regimen lost more belly fat than those who followed a low-intensity plan reports Health.com. (In fact, the low-intensity exercises experienced no significant changes at all.) "You need to exercise at full intensity because the end goal is to burn more calories, and high intensity exercise does just that," says Natalie Jill, a San Diego, Calif.-based certified personal trainer. High intensity workouts mean you're going all out for as long as you can. If this sounds intimidating, think of it this way: you'll burn more calories in less time.

You're doing the wrong workout

A daily run or Spin class is great for your heart, but cardio workouts alone won't do much for your waist. "You need to do a combination of weights and cardiovascular training," says Sangeeta Kashyap, MD, an endocrinologist at Cleveland Clinic. According to Health.com, strength training increases muscle mass, which sets your body up to burn more fat. "Muscle burns more calories than fat, and therefore you naturally burn more calories throughout the day by having more muscle," says Kate Patton, a registered dietitian at Cleveland Clinic. Patton recommends 250 minutes of moderate-intensity exercise or 125 minutes of high-intensity exercise a week.

You're getting older

As you get older, your body changes how it gains and loses weight. Both men and women experience a declining metabolic rate, or the number of calories the body needs to function normally. On top of that, women have to deal with menopause. "If women gain weight after menopause, it's more likely to be in their bellies," says Michael Jensen, MD, professor of medicine in the Mayo Clinic's endocrinology division. In menopause, production of the hormones estrogen and progesterone slows down. Meanwhile, testosterone levels also start to drop, but at a slower rate says Health.com. This shift in hormones causes women to hold onto weight in their bellies. The good news: you can fight this process.

You're doing the wrong exercises

Doing crunches until the cows come home? Stop it! When you're down to your final inches of belly fat, the dreaded crunch won't be the exercise that finally reveals your six-pack. "You can't spot reduce," Jill says. Instead, she suggests doing functional exercises that use the muscles in your core—abdominals, back, pelvic, obliques—as well as other body parts. "These exercises use more muscles, so there is a higher rate of calorie burn while you are doing them," she says. Planks are her favorite functional exercise—they activate not just your core muscles but also your arm, leg, and butt muscles.

Doing crunches until the cows come home? Stop it! When you're down to your final inches of belly fat, the dreaded crunch won't be the exercise that finally reveals your six-pack. In this photo, participants work out during the Tone It Up Beach Workout with Katrina Hodgson and Karena Dawn on May 13, 2015 near the Hermosa Beach Pier in Hermosa Beach, California. Jonathan Moore/Getty Images for Tone It Up/AFP

You're eating the wrong fats

The body doesn't react to all fats in the same way says Health.com. Research correlates high intake of saturated fat (the kind in meat and dairy) to increased visceral fat, says Patton. On the other hand, monounsaturated fats (the kind in olive oil and avocados) and specific types of polyunsaturated fats (mainly omega-3s, found in walnuts, sunflower seeds, and fatty fish like salmon) have anti-inflammatory effects in the body, and if eaten in proper portions may do your body good. But Patton warns that eating too much fat of any kind increases your calorie intake and could lead to weight gain, so enjoy healthy fats in moderation

You're eating too many processed foods

"Refined grains like white bread, crackers, and chips, as well as refined sugars in sweetened drinks and desserts increase inflammation in our bodies," says Patton. "Belly fat is associated with inflammation, so eating too many processed foods will hinder your ability to lose belly fat." Natural foods like fruits, vegetables, and whole grains are full of antioxidants, which have anti-inflammatory properties and may therefore actually prevent belly fat, Patton says.

You're stressed

Tight deadlines, bills, your kids—whatever your source of stress, having too much of it may make itharder for you to drop unwanted pounds, especially from your middle according to Health.com. And it's not just because you tend to reach for high-fat, high-calorie fare when you're stressed, though that's part of it. It's also due to the stress hormone cortisol, which may increase the amount of fat your body clings to and enlarge your fat cells. Higher levels of cortisol have been linked to more visceral fat.

You're skimping on sleep

If you're among the 30% of Americans who sleep less than six hours a night, here's one simple way to whittle your waistline: catch more Zs. A 16-year study of almost 70,000 women found that those who slept five hours or less a night were 30% more likely to gain 30 or more pounds than those who slept 7 hours. The National Institutes of Health suggest adults sleep seven to eight hours a night.

You're apple shaped

If you tend to pack the pounds around your middle rather than your hips and thighs, then you're apple shaped. This genetic predisposition means ridding yourself of belly fat will be harder, Dr. Kashyap says, but not impossible.

You're sick

If your testosterone levels are high—something that can occur with polycystic ovary syndrome (PCOS)—you might have difficulty losing weight. "If you're an apple shape and overweight, it's a good idea to see your doctor," Dr. Kashyap says, since there may also be a chance that you are prediabetic or diabetic

You're unmotivated

Are you committed to the work needed to lose belly fat? "Reducing belly fat takes a combination approach of a low-calorie diet that is high in fiber and low in carbohydrates and sugar along with cardiovascular and weight training," Dr. Kashyap says. "If you are willing to do the work, you can move past genetics and lose it."