Overweight - body mass index; Obesity - body mass index; BMI

Overweight and obesity mean having a weight than is higher than what is healthy for a given height. A person may be overweight from extra muscle, bone, or water, as well as too much fat. But both terms mean that someone's weight is higher than what is thought to be healthy for their height.

More than 1 out of every 3 adults in the United States is overweight.

Different types of weight gain

Weight gain in the area of and above the waist (apple type) is more dangerous than weight gained around the hips and flank area (pear type). Fat cells in the upper body have different qualities than those found in hips and thighs.

Lipocytes (fat cells)

When energy input is equal to energy output, there is no expansion of fat cells (lipocytes) to accomodate excess. It is only when more calories are taken in than used that the extra fat is stored in the lipocytes and the person begins to accumulate fat.

Obesity and health

Obesity increases a person's risk of illness and death due to diabetes, stroke, heart disease, hypertension, high cholesterol, and kidney and gallbladder disease. Obesity may increase the risk for some types of cancer. It is also a risk factor for the development of osteoarthritis and sleep apnea.