Obesity is an excess of body fat. Usually, anyone who is 20 percent over the normal weight for his or her age, sex, build, and height is considered obese.

How much a person weighs is only part of the story, however. Perhaps more important than weight is the percent age of fat in the body. For healthy women, fat can account for as much as 25 percent of body weight; 17 percent is a healthy percentage for men. Women's bodies are designed to carry a higher proportion of fat tissue to ensure that there is plenty of fuel for pregnancy and nursing, even if food is scarce.

The average human body has 30 to 40 billion fat cells. Most of the extra calories we eat that we do not need for immediate energy are stored as fat. in modern society, storing energy as fat is no longer necessary for most people. Most North Americans wait no more than four hours between meals and snacks. So instead of being a valuable survival mechanism, the body's ability to store fat now is more likely to have a profoundly negative effect on health. As fat accumulates, it crowds the space occupied by the internal organs. Obesity - even moderate overweight - puts an undue stress on the back, legs, and internal organs, and this can eventually exacerbate many physical problems and compromise health. Obesity increases the body's resistance to insulin and susceptibility to infection, and puts one at a higher risk for developing coronary artery disease, diabetes, gallbladder disease, high blood pressure, kidney disease, stroke, and other serious health problems that can result in premature death. Complications of pregnancy and liver damage also are more common in overweight individuals. Obese persons suffer psychologically as well as physically, because our society tends to equate beauty, intelligence, and even success with thinness.

The most common causes of obesity are poor diet and/ or bad eating habits and a lack of exercise. Other factors that can lead to obesity include glandular malfunctions, diabetes, hypoglycemia, emotional tension, boredom, and a simple love of food. Obesity has also been linked to food sensitivities and/or allergies. Food your body cannot use or that is a poison to your system is stored in the tissues and causes water retention. Ironically, poor nutrition may be an important factor in obesity. When there is inadequate intake of certain essential nutrients, fat is not easily or adequately burned and can accumulate in the body.