Weight Loss Drugs for Obesity, Helpful Treatment (cont.)

"Lifestyle is a big factor in why people gain weight," Wyatt tells WebMD. "But there's a definitely a genetic and a physiologic reason, too. Because of differences in physiology, some people will just have a harder time losing and maintaining weight than others."

George A. Bray, MD, professor of medicine at Louisiana State University, agrees that the traditional view of obesity -- as essentially a moral failing -- is wrong.

"Are people who are massively overweight because they lack [the hormone] leptin 'weak-willed'?" asks Bray. "No, and, in fact, some kind of neurochemical derangement probably underlies most obesity."

"It's cruel and hurtful to categorize overweight and obese Americans as 'lazy' or 'weak-willed,'" he says, "and to conclude that all they need to do is just push themselves away from the table."

Obesity as a Disease

Obesity is a killer. So is it enough for a doctor to tell a chronically obese person to lose weight and leave it at that? Wyatt and Bray both point out that we routinely use medication for other conditions that can be controlled by changes in diet and exercise.

For instance, diabetes and high blood pressure can both be helped substantially by changes in your lifestyle. But doctors still prescribe medication for both conditions. It would be highly unlikely for your doctor to refuse to give you diabetes medicine simply because you could control the disease with more exercise and a stricter diet but don't. Everyone knows that permanent lifestyle changes are very hard to make, Wyatt says.

"We don't punish diabetics or people with high blood pressure by withholding medicine," says Wyatt. "So why should we punish people with obesity? If you have a medication that will make it easier for people to lose weight, why not use it?"

Wyatt and Bray both stress that anyone who needs to lose weight should try lifestyle changes first. But for those who can't seem to do it with exercise and diet alone, weight loss drugs could help.

The Causes of Obesity

At the most basic level, your weight is determined by the balance between the amount of energy you take in and the amount you expend -- the food you eat and the calories you burn. If you burn more calories than you eat, you'll lose weight; if you eat more than you burn, you'll gain.

However, while that equation is still roughly true, researchers have found that it's a lot more complicated. The body has many complex and interacting mechanisms that help regulate your weight.

One of them is the hormone leptin, which is secreted by fat cells. Your brain detects the amount of leptin in your system and uses it as a kind of barometer. Not enough leptin presumably means that you need more food; enough leptin is a sign that you've eaten as much as you need, and your brain triggers feelings of fullness. The problem is that many obese people are leptin-resistant. Their brains don't correctly detect the amount of leptin in the system, "thinking" that the level is lower than it really is. As a result, a leptin-resistant person will keep feeling hungry after a person with normal leptin levels would feel full.