Obesity invariably leads to Metabolic Syndrome resulting in glucose intolerance or hyperinsulinaemia (high blood insulin levels), hypercholesterolemia (high blood lipid levels) and hypertension (high blood pressure). There are over 60 different diseases, disabilities and dysfunctions associated with obesity, metabolic syndrome, physical inactivity and poor nutrition that include numerous cancers, diabetes, a variety of cardiovascular and cardiorespiratory diseases, etc. It is estimated that approximately 70% of Americans over the age of 25 years have at least one component of metabolic syndrome and an alarming increase of metabolic syndrome in those under 25. Most medical and health experts believe that both obesity and metabolic syndrome are largely preventable with regular exercise and proper nutrition.
Body mass index (BMI) is the simplest and most often used measure for body fat (BMI: kg/m2). The recommended BMI for good health is 20-25 for both males and females. Most athletes are considerably lower. One major criticism of BMI is that it does not consider lean body mass and very muscular athletes with their abs showing can be classified as obese according to their BMI measure. In answer to that criticism, most medical experts respond if your abs show or you are muscular and athletic, you really arent worried about obesity, are you?
BMI between 25 and 27 is considered overweight, between 27 and 30 is considered moderately obese, between 31-40 markedly obese, and 40+ morbidly obese.
These measures can be compared to the measures used in body composition analysis, which compares how much of the patients body is lean tissue (muscle, bone, etc.) vs. how much is fat.
Another popular and easy measure for obesity is the waist to hip ratio, which should be less than 0.85 for females and less than 1.0 for males.
Obese individuals face difficult challenges to fat loss due to their inefficiency in many of their physiological systems. Long term success is dependent on incorporation of an exercise program. Weight loss through diet alone, without exercise, causes a dramatic reduction in basal metabolic rate (BMR). BMR accounts for a large percentage of total daily caloric expenditure and is related to age, sex, body surface area and lean body mass. Diet without exercise causes the BMR to decline by 15-20%, partially because of loss of muscle mass and an increase in metabolic efficiency (the body uses less energy for normal functions). Regular exercise may also prevent the progression from hyperinsulinaemia to impaired glucose tolerance to Type II diabetes. More than 90% of people with Type II diabetes are obese and weight gain as an adult is especially associated with this disease. Insulin sensitivity and glucose tolerance may be significantly improved with only a 5-10% loss of body mass. Exercise without weight loss may also enhance insulin sensitivity. Even a single exercise session may stimulate glucose uptake for 24-48 hours.
Energy expenditure should exceed 300 kcal/exercise session. Keep in mind that there is approximately 3500 kcal/pound of fat. Circuit training type programs with 45-60 second work intervals and 15 second rest intervals have proven effective by increasing energy expenditures and adding muscle mass for overweight and obese patients. Some type of exercise (aerobic or anaerobic) should be performed daily, but as a minimum 3-4 times per week. Some studies show that multiple 10-minute sessions of physical activity may be as effective for weight loss as traditional continuous exercise sessions. Obese patients show greater long-term compliance at lower aerobic intensities of 40-60% VO2max due to low fitness levels, less chance of injury, and greater fatty acid mobilization from fat tissue (at intensities below 75% VO2max).
There is evidence of greater loss of subcutaneous fat with high-intensity exercise. If your clients can tolerate high-intensity and are cleared by their doctor, then by all means encourage them to incorporate high-intensity exercise in their program, but most important: THEY MUST EXERCISE!