Body Fat and Obesity

Obesity will someday be the number one killer in the United States!! However, you may not believe this statistic because it may not be obesity itself that kills, but rather the underlying diseases that stem from it. As the body mass index rises, so does the mortality rate from cancer, heart disease, and disease. For example, obesity may be related to any number of diseases including:

Cancer: For men, obesity increases the chance of colon rectal and prostate cancer. Obese women are more likely to develop breast, uterine, ovarian and gall bladder cancer.

Respiratory difficulty: The diaphragm of obese individuals must push their fat out of the way in order to breathe. This leads to reduced tidal volume (the amount of air inhaled with each breath) and reduced energy. Since exercise increases the demand for breathing, obese people are less likely to exercise.

Heart Disease: Obese people often have high blood pressure and elevated total blood cholesterol. Total cholesterol can be reduced with every pound lost. For people with a BMI of 29+, the risk of coronary heart disease triples. Excess fat in the abdomen means there is a greater danger of cardiac disease as compared to fat deposited in the thigh (lower extremity). Abdominal fat for men is usually found in the upper abdomen whereas female fat deposits are more common in the lower abdomen.

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Before we continue, it is important to be familar with some key terms and definitions regarding obesity and disease.

Triglycerides are the form of liquid fat that is stored in adipose (fat) cells. The higher your blood triglyceride levels, the more fat you have in storage. Normal values are <200, but when triglycerides in the blood reach 400 mg/dL, a given person is at a high risk for cardiac disease.

Normal fasting blood sugar should be <110 mg/dL. Blood sugar between (110 - 125 mg/dL) is a sign of glucose intolerance and when it reaches 126 mg/dL diabetes is diagnosed.

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BMI (body mass index) is used to study large populations and to compare obesity in America from generation to generation. People with large amounts of muscle score high on BMI but do not have health risks related to obesity. The odds of becoming arthritic increase as BMI increases. The chance of stroke rises as well with elevated BMI.

BMI = weight (kg)/height (m²). (To convert you weight into kilograms (kg), divide your weight in pounds by 2.2)

Forget the weight tables. Weight is used to determine % body fat and ideal body weight. Otherwise it is unimportant. We should be concerned with reducing our % body fat rather than weight loss. This is not just a cosmetic consideration. The fat beneath our skin reflects the fat surrounding our organs. An increase in visceral fat is associated with increased risk of cardiovascular disease.

Your ideal body weight is determined by adding your desired % body fat to your lean body mass (LBM). Exercise physiologists will help you find these values. It is estimated as follows:

1. Estimate % body fat using skin fold measurements and an appropriate formula.
2. Determine your fat weight in pounds: (body weight x % body fat = pounds of fat).
3. Find lean body mass (LBM). Lean body mass is the percent of body weight that consists of muscle and bone.
   LBM = body weight - pounds of fat.
4. Ideal weight = (LBM x desired % body fat + LBM).

An ideal body fat will always depend on age and gender.

Ideal Body Fat Percentages (according to the Aerobic Research Institute).

AGE	Men	Women
<30	13%	18%
30-39	16.5%	20%
40-49	19%	23.5%
50-59	20.5%	26%
60+	20.5%	27.5%

During an exercise program your weight may stay the same or increase. As long as your waist measurement is reduced you are loosing fat even if you are gaining muscle weight.. Muscle weighs more than fat, but fat takes up more space in the body. This is a good thing! Adding more muscle tissue will alwyas increase the amount of calories you burn at rest.