The hormonal regulation of appetite is very strong. Willpower alone is not sufficient to overcome these biological drives. Thus, medications are increasingly being used because they can help overcome some of the biological changes that drive appetite. And there are more obesity medications available today than ever before.

The two primary hormones that control appetite are ghrelin and leptin. They serve as biological on/off switches. Ghrelin is mainly produced in the lining of the stomach and switches on appetite. Leptin is secreted by fat cells and turns off appetite by signaling when you’re full.

Most people who are very overweight have, at some point, tried to majorly cut calories—and failed, says Scott Isaacs, MD, a clinical instructor of medicine at Emory University School of Medicine and medical director at Atlanta Endocrine Associates. While it's true that they're probably eating too much, they're doing so because they're hungry, he explains. "Telling someone to eat less is a lot like telling them to breathe less," he explains. "They can do it for a while, but eventually biology is going to win out."

If trying to clean up your diet just leaves you more ravenous and frustrated, you’re not alone. Time to learn how your eating decisions affect your appetite a.m. to p.m.

Produced by fat cells, leptin signals to the brain how much fat is in the body, explains Dr. Scott Isaacs, medical director of Atlanta Endocrine Associates. When leptin levels are low, you tend to feel hungry, and when leptin levels are high, you tend to feel full.

However, some studies have found that only 5 percent of people have a TSH above 2.5 (though others say it's more like 15 percent). That is to say, being above 2.5 is statistically abnormal. And abnormalities are, by and large, how medicine decides what a disease is.

Diabetes information is everywhere—blogs, online forums, small talk with friends and family, terrifying lawyer ads on TV. Keep in mind that everyone’s situation is different and some sources are more reliable than others, Dr. Isaacs says. Your diabetes care team can guide you toward the truth and help you make the best choices for your health.

Your metabolism is partly ruled by genetics, but you can rev it up naturally by eating right. Fill up on the following nine foods to increase your body's fat-burning power.

There are two colors of fat, brown fat and white fat. The fat we are most familiar with is white fat, which comprises most of the fat in the body. Most of the fat in our body is white fat. White fat is a storage depot for excess calories and provides insulation. White fat produces inflammation, an unhealthy situation for the body. Brown fat is a healthy type of metabolically active fat. Brown fat is named as such because it contains a lot of energy-generating mitochondria which gives rise to the color. Brown fat is considered “good” fat because it burns calories and generates body heat. There are different types of fat. Fat is actually a series of different types of tissues with different functions. The location of fat matters and that fat in the belly is the unhealthiest type of fat that leads to many of the problems we associate with obesity including insulin and leptin resistance. But location is not the only factor that distinguishes different types of fat.

If you store your leftovers in plastic, keep old receipts lying around or think nothing of eating an unwashed grape or two, you could be exposing yourself to chemicals that impede weight loss. "These substances slow your metabolism and increase appetite or alter hormones such as estrogen in the body to cause weight gain," says Scott Isaacs, M.D., an endocrinologist and author of Beat Overeating Now!