Exercise and Weight
An article in Medicine & Science in Sports & Exercise (vol.21, No. 1, 1989) entitled, "Exercise reverses depressed metabolic rate produced by severe caloric restriction" says dieting slows the body's metabolism and exercise can correct it.
One problem with dieting is that it slows metabolism. If you're trying to lose weight, a slow metabolism actually causes you to store fat. Most people who have dieted find that although there is some initial weight loss, the weight not only returns, but there is more weight than originally.
This study showed that 500 calorie-a-day diets slowed the metabolism by 87%! This is a dramatic depression in body function. Using 1,000 calorie diets, metabolism decreased by 24%. When you want to lose weight, in the form of fat, the metabolism must be increased.
The most effective way to increase the metabolism is by easy exercise. This study showed that only thirty minutes of daily exercise, a decrease in metabolism could be prevented. The subjects jogged, swam or rode stationary bicycles at 60% of their maximum effort, which is a very easy pace.
Many important nutrients are necessary for burning off that extra body fat. Too often, restricting food intake results in missing out on some of those necessary nutrients.
More on Fat Loss and Metabolism
An article in Medical Hypothesis, (1989. 28, 13-33) entitled "Prostaglandins, Brown Fat and Weight Loss," outlines some rules for healthy weight and fat loss, and helps dispel certain myths that have become traditional strong-holds in weight loss programs.
The authors, from Princeton's Brain Bio Center, stress the necessity of increasing the metabolism in overweight individuals as a means of weight loss. People who are overweight generally have a lower metabolism, and it is through this increased metabolism that fats and carbohydrates (and at times protein) are "burned."
There are three ways the body's metabolism "burns" calories: 1) during rest, 2) during activity and exercise, and 3) during heat production. All three areas play a vital role in weight loss. Let's look at each area separately.
1. The resting state potentially can burn the highest amount calories—73% of our calories. One goal of any healthy weigh loss program is to increase the calories burned during resting. This is accomplished by the two remaining factors:
2. The fact is that inactive overweight people and lean people usually have the same level of physical activity. The difference is the lean person has a higher metabolism. Although physical exercise uses only about 12% of the daily calories burned, exercise causes the calories burned during the resting state to be dramatically increased. The calories burned during exercise, are almost insignificant compared to the increased metabolism resulting from exercise. Here, the total calories burned may be twice that of the exercise itself.
3. The body's heat production accounts for 15% of the total energy used. This process, called thermogenesis, is highest during food intake and exposure to cold. The consumption of a meal can increase the metabolism, thereby burning more calories. And, exposure to cooler temperatures (below 71ƒF) has a stimulating effect on the metabolism. This effect is due to the presence of brown fat. One of the most important regulators of heat production is the thyroid gland. People who complain of feeling cold, and have low temperatures, often have low thyroid gland function. As discussed below, certain foods can increase markedly, the amount of calories burned during thermogenesis.
The authors recommend the following exercise habits to optimize weight loss:
a. Exercise in an environment below 71ƒ F if possible, such as Outdoors in cool weather. Avoid over-heated exercise areas indoors.
b. Take cool showers before and/or after exercise.
c. Avoid over-dressing. Wear loose-fitting clothing when exercising. Avoid sweat-suits which hold the heat and promote sweating.
d. Preferred exercises are continuous, rhythmical and '"aerobic' in nature. Some of these are walking, running, rowing, skating, skiing and swimming. After 30 minutes of exercise, the body "burns" more fats for energy.
e. The authors recommend a minimum of 20-30 minutes per exercise session, at least three times per week.
f. Lifestyle changes are also recommended: taking the stairs instead of an elevator if possible, or parking the car further away from the store.
The authors discuss the third category, diet, in more detail. Specifically, how certain dietary factors can change metabolism
Certain dietary factors can suppress (decrease) metabolism:
… A low calorie diet (caloric restriction) and short term fasting. A common example is skipping meals.
… Snacking throughout the day on high sugared foods (candy, colas, cakes, gum). Also, eating or drinking sweets before exercise prevents proper benefits.
Certain dietary factors can stimulate (increase) the metabolism:
… Dietary fats. Including vegetable oils like extra virgin olive or safflower. These fats contain "essential fatty acids." Following digestion they are converted to substances called prostaglandins which help increase metabolism.
… High fiber foods including whole grains, fresh vegetables and fruits.
… Since certain nutrients are often low in dieters, the frequent self-imposed food restriction often restricts these vitamins and mineral even more. Vitamin B-6, zinc, manganese, and other important nutrients help convert fats to prostaglandins along with other processes important to increase metabolism. Consult your doctor for specific needs.
… Capsaicin, a naturally occurring substance found in hot spicy foods like Mexican chili peppers, stimulates the metabolism. The authors recommend including small amounts of capsaicin in the diet, if tolerated.
… Natural carbohydrates, including whole grain foods (breads, brown rice, pasta) fruits and vegetables, also help to stimulate the metabolism. Conversely, protein foods, such as meat and fish, can slow the metabolism.
Alternating a high calorie day with a low calorie day has a stimulating effect on the metabolism. The example given for men: one day consume 1700 calories, the next day 1200 calories, the third day 1700, the fourth 1200, etc. For women, 1400 calories the first day, and 1000 the next, is sufficient.
… Eating 3-6 meals per day has a stimulating effect on metabolism. 55% carbohydrate, 25% fat and 20% protein is recommended. All white flour and sugar are to be avoided.
Finally, the authors say that when people eat more food, including fats, they still lose weight despite the increased caloric intake.