With the worldwide obesity epidemic, many individuals are searching for ways to lose weight and keep it off. While the focus is often on total body weight, it is actually excess body fat that represents the real health threat. Thus it is important to understand the role that body fat plays in health and disease and how to achieve a healthy level of body fat.
Overweight or Obese
An individual’s body weight or body weight loss composition reflects the level of lean body mass (tissue, bone and muscle) and body fat. While the words obese and overweight are used synonymously there is a great difference between these terms in both definition and associated health risk.
Overweight is defined as a body weight above an acceptable weight in relation to height. This term can be misleading because it does not distinguish between excess body fat and lean muscle mass. For example, it is possible to be overweight without being obese. A body-builder would be an example of this scenario. Having a greater proportion of muscle mass would make this individual appear overweight according to standard weight/height charts, yet this person could have low body fat and be in good physical shape.
The body mass index (BMI) is commonly used to determine whether one’s weight represents health risk. BMI is calculated by dividing weight in kilograms by height in meters squared (kg/m2). A BMI of over 25 kg.m2 indicates overweight. When percentage of body fat is used, women with 25.1 to 29.9 percent and men with 20.1 to 24.4 percent are considered to be overweight.
Obesity is defined as having excess weight loss body fat in relation to lean body mass. By generally accepted standards, men with greater than 25 percent, and women with more than 30 percent body fat, are considered to be obese. When the BMI is used, individuals with a value of greater than 30 are considered to be obese.
Since it is excess fat (not excess weight) that is a health concern, when assessing your overall fitness level it is important to look at the percentage of your body that is composed of fat, rather than just total body weight.
Factors Affecting Body Fat
There are many factors that regulate your level of body fat, including:
· Activity level
· Basal metabolic rate (rate at which calories are burned at rest)
· Hormones, such as insulin, thyroid, and growth hormone
Health Risks of Excess Body Fat
Carrying excess body fat is linked to some of our greatest health threats, namely heart disease, cancer and diabetes. The greater the degree obesity – the greater the health risk. Conversely, maintaining a lean, healthy body can help to reduce your risk of developing these diseases.
Obesity is a known risk factor for developing heart disease. The excess body fat creates an increased workload and stress to the heart, leading to high blood pressure, irregular heartbeat, and enlarging of the heart. Obese people also tend to have high cholesterol levels, making them more prone to arteriosclerosis, a narrowing of the arteries caused by buildup of plaque. This condition can become life threatening if vital organs such as the brain, heart or kidneys are deprived of blood.
Excess body fat can also increase one’s risk of developing cancer. The American Cancer Society has published a report illustrating the relationship between obesity and cancer mortality. Based on the observed association, the American Cancer Society estimated that current patterns of overweight and obesity in the United States could account for up to 14% of all cancer deaths in men and 20% in women.
Obese men are more likely than non-obese men to die from cancer of the colon, rectum, or prostate. Obese women are more likely than non-obese women to die from cancer of the gallbladder, breast, uterus, cervix, or ovaries.