Q: Why is weight loss so emphasized for people with type 2 diabetes? A: Excess body fat increases insulin resistance and type 2 diabetes is primarily a condition of resistance to insulin. Approximately 80% of the people with type 2 diabetes are overweight at diagnosis. Consequently, weight loss tends to reverse this disorder in most people and some are able to eliminate medication and rely solely on exercise, diet, and blood glucose monitoring.
Insulin resistance is in part due to lack of insulin receptors on the outside of the cell membrane of various tissues which reduces the binding of insulin to the cell. Once insulin is bound to the cell membrane, a protein within the cell must travel to the outer region of the cell where glucose is available. This protein, called glucose transport protein-4 (GLUT-4) is deficient in people with insulin resistance. Guess what? With weight loss, whether by dietary alteration or exercise, insulin resistance is lessened because new insulin receptors develop on the outer cell membrane and more glucose transport protein-4 is produced. Thus, the cells improve their ability to use glucose and respond to the signal of insulin. So, you can see why weight loss is emphasized so greatly in management of type 2 diabetes.
Next month’s column will summarize the latest research on weight loss and obesity. Start building your motivation now! To get started, start walking daily and reducing your intake of fats (consult your physician if you have not been exercising).
This month’s article is a follow up from one last month that addressed the question about why weight loss is emphasized in the management of type 2 diabetes. This month’s column deals with research about the effectiveness of various means of losing weight.
Q: What is the best way to lose weight? A: First, let’s modify the question to “What is the best way to lose fat?” and secondly, add the phrase “and keep it off.” First, many people realize it’s fairly easy to lose 5, 10, even 15 pounds, but few people are able to sustain the loss. What’s the problem here? Are so few people really motivated or disciplined enough to maintain a weight loss? Probably not, but most people are not approaching the problem in a sound way.
Typically people lose some weight in the first week or so of a diet comprised of fewer calories than normal. If the loss is more than a pound or two per week, much of the weight lost is actually water and some is even muscle tissue. To maximize the loss of actual fat rather than water and muscle. The weight loss must be accomplished quite slowly, no more than about one-half pound per week for smaller people and one pound per week for larger people. This is disgustingly slow, but it does assure that the weight loss is mostly fat rather than muscle. Nearly all diets cause some loss of muscle, metabolically a very active tissue. The only way to curb this is to use exercise as a means of burning extra calories. In addition, exercise stimulates muscle growth and at least muscle maintenance even in spite of a caloric reduction. The most effective exercise to do is resistance training or weight training.
If muscle tissue is lost while on a 10 day “wonder diet,” which it surely would be, then once normal eating patterns are reestablished one needs fewer calories. Consequently, one now possesses even more fat than initially. This cycle of weight loss/muscle loss and rapid regain to even a higher level of body fatness is called the “yo-yo diet syndrome.” It is worse than never having dieted in the first place!
The main dietary correlate of obesity is not consuming too many calories but rather the amount of fat in the diet. Fat is related to a number of common medical problems including obesity, type 2 diabetes, several types of cancer, and cardiovascular disease. For these reasons, reduction in dietary fat is advised by most health and medical groups. How little fat should be consumed? While the answer is still being sought by researchers, previous work indicates that 30% of one’s daily calories should be the upper limit. A diet of 10% fat is a spartan vegetarian diet which can certainly be healthy and has been shown to even remove some of the plaque (the hardening of the arteries) in the large arteries. However, it is rather stringent and may be difficult to adhere to unless one was trained in a special program such as the Dr. Dean Ornish Program for cardiac patients. Start with a diet that is 30% fat and slowly reduce the fat content to a levels you feel comfortable with. In theory, the lower the percent of fat the greater the weight loss and maintenance loss will be. This is because one gram of fat yields 9 calories while carbohydrates and protein liberate only 4 calories per gram. Secondly, excess calories from carbohydrate require about 7 times the energy to synthesize new fat than do excess fat calories. So, excess fruits, vegetables, and grains do not easily cause weight gain.
Genetics is certainly a factor in ideal body weight and in weight gain. Studies with twins as subjects show a significant relationship regarding how much weight is gained from overeating, and even where the excess fat is deposited. Some folks can add nearly 10 times as much body fat from overfeeding as others. Not fair, but heredity is a factor. We have two choices: be realistic in setting a weight loss goal, and choose your parents wisely!
So putting it altogether, lose weight very slowly with a diet relatively low in fat and high in complex carbohydrates, exercise aerobically 30 minutes daily and lift weights 2 or 3 times a week to build and maintain muscle mass and hence elevate the metabolic rate. Be realistic in your goal. Even with a 10 to 15 pound loss that is maintained, many good things will happen to you: improved insulin sensitivity, reduced cholesterol and triglyceride levels, reduced blood pressure, and improved self-concept and energy. These benefits make such a lifestyle worthwhile even without weight loss!