It is a well documented fact that over 95% of people who diet end up gaining their weight back within a couple of years. Obviously there are a lot of reasons for this. Perhaps the most important reason goes to the very concept of “dieting”. Unfortunately, most dieters change their caloric intake (often drastically) for a certain period of time but then when their diet is “over” they simply return to their previous eating habits. This makes no sense and goes to the oft-quoted definition of insanity “doing something over and over and expecting a different outcome”. Short term weight loss, while perhaps satisfying a New Year’s resolution, preparing for a cruise or a wedding or High School reunion doesn’t really change health risk factors to any significant degree. The later requires a long term change not so much in terms of weight but in terms of body fat levels.
Dieters focus on weight. Most people have a certain weight that they feel they should be. The focus on weight and BMI, (weight divided by height), particularly by the medical establishment (even researchers) and the insurance industry has reinforced this. Weight and body fat are not necessarily tethered. It is excess body fat, particularly intra-abdominal or visceral fat that causes all the diseases associated with overweight or the better term, over-fat.
Weight bearing joints (hips, knees, ankles, feet) care about body weight but every other illness related to “overweight” is due to excess body fat, not weight. Excess body fat increases insulin levels, which leads to hypertension, elevated LDL and triglycerides, diabetes, heart disease and even some cancers. The diseases of industrialized nations are due to excess inflammation and fat cells that are packed with fat produce inflammatory substances.
One of the pitfalls of losing weight instead of focusing on body fat is that it leads to a drop in metabolic rate (BMR) since BMR is almost completely determined by lean body mass (LBM) or muscle. Weight loss without maintenance of muscle lowers BMR so more calories are stored (as fat) instead of burned for energy. This of course will lead to cycling, or yo-yoing essentially setting people up for a vicious cycle of dieting for a weight goal, losing muscle, dropping BMR, storing more calories as fat and then simply repeating this cycle.
There are several ways to measure body fat and LBM, some more accurate or convenient than others. Please see part II of this discussion to learn about the different techniques to measure these parameters. The various dietary interventions utilized to result in loss of fat with maintenance of muscle and BMR will follow as well.