Anti-obesity drugs or weight loss drugs are pharmacologically active agents that directly or indirectly change one of the fundamental biological functions of the body, weight management, by changing either appetite or glucose absorption. Appetite is a primary driver of energy metabolism and caloric intake. As appetite decreases, calories are absorbed less and fat is burned to meet energy requirements. This approach balances energy use between dieting and exercise.
The most widely used fat absorber in humans is the orlistat, a patented fat-suppressing plant component extracted from the root orchid tree of India. Orlistat has been clinically proven to favorably affect lipid (fat) levels, insulin sensitivity and glucose homeostasis, and to inhibit the extrusion of fat from adipose tissue. It was first tested in patients with overweight or obesity and found to moderately reduce body weight after stopping the diet and exercise. A phase II clinical trial comparing orlistat with a high-glycemic index diabetic diet showed that patients taking orlistat had significantly lower blood sugar levels than those on a high-glycemic index diet only.