Sure, abdominal fat isn't flattering, but that's the least of your worries. The amount of belly fat--and the type can lead to several health problems. There are two types of abdominal fat--subcutaneous fat lies just below the skin and on top of the abdominal muscles; visceral fat lies deep in your abdomen and wraps around internal organs. Visceral fat is particularly unhealthy; a tell-tale sign that you have it is when your "beer belly" feels hard.

In early adulthood women tend to carry fat in their hips and thighs, while men pile on the pounds in their abdomens. Previously, the common belief was that fat just hung around in the abdomen waiting to be burned off as energy. However, researchers now know that abdominal fat is biologically active and contributes directly to health problems such as heart disease, hypertension, some forms of cancer--and several others: 

Health Problems Caused By Belly Fat

• Hormonal problems. According to Harvard Medical School (HMS), abdominal fat acts like an endocrine gland or organ. It produces hormones and other chemicals and affects their function - hormones such as leptin, which affects your appetite

• Insulin insensitivity and diabetes. Another hormone abdominal fat influences is adiponectin, according to HMS. This hormone may influence how cells respond to insulin. Insulin insensitivity is also a risk factor for developing type 2 diabetes, the most common form of diabetes which increases risks of heart disease, kidney disease, nerve damage and blindness.

• Stroke. Obesity is a major contributing factor to stroke. But, one study found that when other factors were considered - such as hypertension, diabetes, physical inactivity and smoking BMI was less important in stroke risk. The most significant risk factors were waist measurement and waist-to-hip ratio (WHR, your waist measurement divided by your hip measurement). Those who had the highest WHR had a seven-times greater risk of stroke. Plus, participants with the highest amounts of abdominal fat were the most likely to suffer a stroke.

• Erectile dysfunction. Because abdominal fat causes vascular problems and disrupts hormones such as testosterone, it's a contributing factor in impotence and other erectile problems.

• Migraines. Those headaches you're having may not be due to stress, or environmental factors. In a recent study, 20 percent of men between ages 20 and 55 who had abdominal obesity experienced migraine headaches compared to 16 percent who didn't have the condition.

• Alzheimer's. If you have excessive abdominal fat in your 40s you're significantly more at risk for developing Alzheimer's, as well as other types of dementia in your 70s.

• Metabolic risk factors. Visceral belly fat in men has been linked to an increase in liver fat, triglycerides and high-density-lipoprotein cholesterol and total cholesterol.

The Quickest Ways to Burn Your Belly Fat

• Cut calories. When you eat more calories than you burn, weight gain is inevitable. Try to reduce portion sizes at each meal. Choose fish instead of meat, or eat lean cuts of meat. Also, choose low-fat dairy products.

• Cut out refined foods. Ditch the white bread, cereals and pastas and fill up on healthier whole grain alternatives.

• Rev up your activity level. Reducing your calorie intake and exercising is more effective at burning off belly fat than cutting calories alone. Dedicate 30 minutes five days a week to aerobic exercise such as jogging, biking or swimming. Weight lifting also helps to rid your body of excess abdominal fat; aim for 2 ½ hours or more each week.

• Ban the booze. It's not called a "beer belly" for nothing. Even though it isn't the primary cause of extra abdominal fat, it doesn't help. Also, overindulging in alcohol is more likely to cause visceral belly fat in men than women.

• Butt out. Here's yet another reason to quit smoking: While smokers tend to be slimmer than non-smokers, they carry more belly fat.

• Get more sleep. Hormones that affect your appetite - leptin and ghrelin - are produced when you're asleep. Being sleep deprived reduces the levels of these hormones in your body, which makes you more likely to overeat and to not feel full after eating.

Sources:

Stroke, published online August 2008. "Contribution of Obesity and Abdominal Fat Mass to Risk of Stroke and Transient Ischemic Attacks." Tobias Back et. al.

AJP-Endocrinology and Metabolism, June 2003, 284(6). "Visceral fat and liver fat are independent predictors of metabolic risk factors in men." Robert Ross et. al.