First of all, there are three major components of a permanent weight loss program, and they constitute a lifestyle change. They are: 1) a low fat, nutritious diet, 2) aerobic exercise - to burn the fat, and 3) resistance exercise (weight training is good, but simple calisthenics, using body weight, are also good) to improve your energy burning "furnaces". Note that the "best" exercises are the ones you will do.
Important to a healthy diet is lowering the amount of fat it includes, but don't forget that even non-fat food still contains calories, and eating more calories than we "burn up" with our daily activities, leads to fat accumulation. One reason fat should be minimized in our diets is that it takes much less energy for the body to store fat than for either protein or carbohydrate. Protein, eaten in excess, can be converted to fat. And fat is ...... , well, fat.
A healthy diet (only the macro(*) nutrients are relevant for today's discussion) consists of approximately 65% carbohydrate, 15% protein, and 20% fat. These percentages are not absolutes; for instance, some say that 30% fat is acceptable. Maybe, but probably not, especially for anyone who is already too fat. Some claim that more protein is required, especially for athletes. Remember that the function of protein is to build/rebuild body tissue. Our bodies are constantly recycling - cells die and are regenerated. And athletes are continually tearing down muscle cells, which need to be repaired. Normal protein intake (per the RDA) is .8 grams/kg of body weight per day, 1.2 g/kg of body weight per day for athletes - maybe even more, but the fate of excess protein is: 1) small amounts can be converted to energy, 2) it can be eliminated as normal body waste, or 3) it can be converted to, guess what, fat. Carbohydrates are an essential ingredient in our diet. They are converted to glucose, which provides much of the body's energy - fat is another major source, but it requires the presence of carbohydrate to burn (fat burns in a carbohydrate fire). Glucose is also important as the single fuel source for the brain (the CNS). Without carbohydrates, as during starvation, the body begins to cannibalize itself by breaking down muscle tissue to ultimately create glucose. Carbohydrates have long been considered "fat" foods (a bad rap; the problem is typically what is eaten with them), but, as you can see, they are essential, and in large amounts. Remember though, that "simple" carbohydrates (sugars) should be limited because of their high caloric content. Complex carbohydrates (starches, like cereals and grains) should be the major component of one's diet. Also, remember that carbohydrate calories that exceed your body's energy needs get converted to-yes, fat! Note that some extra carbohydrate is beneficial, and is stored in the form of glycogen for later conversion to glucose, BUT, there are limits, and what can't be stored is converted to fat.
(*)A thorough discussion of nutrition includes the Macro nutrients: carbohydrates, fat, and protein; Micro nutrients: vitamins, minerals, and water; and fiber, even though it isn't technically a nutrient - I think we all know what role it plays.
I know this newsletter issue is advertised to be about weight loss, be patient, I'm getting there. We have to get fat before we can lose it. A final subject to discuss before we get to weight loss is metabolism. Metabolism is essentially the process by which food becomes energy; and how much food we need is affected by our basal metabolic rate (BMR(**)) - minimum amount of energy required to sustain the body in the resting state (metabolism is a bit more complex than stated here, but this description will suffice for our purposes). BMR supports breathing, heart beat, etc. Some very simplistic figures are that a female should take in a minimum of 1200 calories/day, and a male 1500/day. Actual figures are computed using body weight.
(**)BMR appears to differ by sex, but it is actually lean body mass, which is typically higher in males; women typically have more "essential fat ," and less lean body mass, hence a lower BMR. This is a good reason why women benefit from weight training.
The point to be made here is that calories in addition to BMR should be ingested to account for physical activities beyond simply maintaining life. The higher one's metabolism rate, the more efficiently calories are burned. Slothful levels of activity, and starvation diets are two very good ways to lower your metabolism, which is not a desired goal.
All right, now it's time to lose weight. We will go over the three components of permanent weight control (control includes desired weight gain, but that isn't relevant to this discussion).
To achieve a realistic weight and keep it there, it is essential that you eat a healthy, balanced diet - foods from the Basic Four - 1) meats, including beans and legumes, 2) dairy products, 3) fruits and vegetables, and 4) breads and cereals. [See MAF FITNESS NEWSLETTER, Vol I, Issue 1, March 1994 for more details.] I highly recommend Covert Bailey's "Fit or Fat" series of books. His "Target Diet" concept is a very simple and practical way to handle the Basic Four. To lose weight, as well as maintain it, cut back on fat (also salt and sugar, for other health reasons), and include lots of water and fiber (also not specifically weight loss items). Fat can be especially insidious for several reasons, but let's concentrate on two. One is that fat contains over twice as many calories (9 per gram) as either protein or carbohydrate (both are 4 calories per gram). Secondly, fat takes less energy to store than either carbohydrates or protein (actually, protein doesn't really get stored like fat or carbohydrates - just used or lost, although excess may be converted to fat. This may be a reason why fat is so easily stored in our bodies.
You may have heard that 3500 calories equals one pound of body weight. Therefore, if a person were to reduce their daily caloric intake by 500 calories, that would yield a one pound loss in one week. This is an acceptable amount to lose per week. But remember that this modest restriction must not cut into the minimum 1200/1500 calories per day required by women/men, respectively, but there is some leeway because daily calories should be more like 2900/day for the average male, and 2200 per day for the average female - these figures are BMR plus extra for daily activities. The problem with dietary restriction alone is that it can slow the metabolism process (the body may think it is being starved, and, therefore, may slow itself down to further conserve energy). It may also cause a loss of lean tissue, which you don't want to happen. You want to lose fat.
Performing aerobic exercise (use of large muscles in a repetitive fashion - e.g., running, bicycling; note that swimming is excellent for muscle toning and cardiovascular improvement, but is not effective for weight loss) at a moderate rate "burns" primarily fat; while higher intensity aerobic exercise burns primarily carbohydrates. As you start running, for instance, fat and carbohydrates provide the energy sources in approximately equal shares. If you continue the exercise for a longer duration, say 30 minutes or more, at a moderate rate, a shift occurs and fat becomes the primary energy source. On the other hand, if you increase the intensity, carbohydrates become the primary source of energy. More important than the calories burned during exercise, is that more than a normal amount of calories are burned for some time after exercise - the so-called "afterburn." Aerobic exercise increases the density of mitochondria in the exercised muscle cells. Mitochondria are organelles (mini-organs - if you will) which collect ATP, which is the body's energy storage form. Muscles are energized for movement when ATP is split. Energy is released as a byproduct of the split. Because mitochondria are especially dense in muscle cells, the more you have, the more energy you can release. This is a significant reason why most weight loss diets doom one to becoming fatter. Typically a person on a "diet" that achieves a quick, relatively large weight loss, loses a lot of muscle along with the fat, which reduces the number of mitochondria, and thereby reduces the ability to keep the fat off. Yo-Yo dieting typically results in fewer mitochondria, and future fat loss becomes more-and-more difficult.