Exercise and Weight Control – A Balanced Approach
Resting metabolic rate (RMR) represents the energy the body expends to maintain life and normal bodily functions, such as respiration and circulation.
Approximately two-thirds of the calories you expend on a daily basis are to support those functions.
If you attempt to lose weight solely by severely restricting caloric consumption, your body responds by conserving energy (i.e. it burns fewer calories).
For example, switching from a 1,800 calorie diet to a 1,200 calories diet will lower RMR approximately 10 percent and an 800-calories diet will lowerit an additional 10 percet.
This compensatory metabolic slow-down lasts well after you’ve completed the diet. When you severely restrict your caloric intake, any body weight that is lost is approximately 50 percent of body fat and 50 percent lean body mass.
In other words, if you lose 30 pounds as the result of a diet very low in calories, you’ve actually only lost 15 pounds of body fat. Half of your weight loss involves a reduction in your level of muscle mass.
The net results is that the less muscle tissue you have the lower your RMR will be. In fact, the more weight you lose through dieting alone the more your metabolic rate declines.
As a consequence, once you abandon your efforts to severely restrict your caloric intake rhythm a relatively short period of time you will more then likely regain much of the weight you’ve lost.
Without question, sensible eating must be an essential part of a sound weight control programme. All individuals, however, will experience more immediate and long-lasting results if they combine exercise with their dieting efforts.
In this regard the key question that must be addressed is what type of and how much exercise is necessary for sound weight management.
What type of exercise is best?
It takes two different types of exercise to help you most effectively lose weight and keep it off. One to burn a high number of calories, aerobic-type exercise, the other to build and preserve muscle tissue, strength-training exercise.
Muscle helps you lose weight and keep it off because it help maintain your RMR, allowing you to burn a greater number of calories when you’re at rest.
An analyst of the available data indicated that, in general, the combination of a conventional aerobic exercise programme with a severely calorie-restricted diet does little if anything to help reserve lean body mass during weight reduction.
It is important to keep in mind that the less lean body mass you have the lower your RMR will be. As a result, it is more likely that you will regain some or all of the weight loss you may have achieved.
On the other hand, if you engage in exercise designed to improve your muscular fitness lvel at the same time you are losing weight, you enhance the likelihood that you will be able to maintain your level of lean body mass.
As a consequence, the optimal exercise prescription for sound weight management is one that combines aerobic conditioning and strength training.
What type of aerobic exercise is best?
Identifying what type of aerobic workout will contribute the most to your weight control efforts involves several factors. Some of them are straightforward and a few of them are subjective in nature.
Despite the massive amount of misfortune that exists regarding the subject, the most appropraite aerobic exercise prescription for weight control is one hat adheres to the American College of Sports Medicine (ACSM) guidelines.
The ACSM recommends that aerobic fitness (and the resultant caloric burn) can be best achieved by exercising three to five times a week, for 20 to 60 minutes at a time, at an intensity level of 60 to 90 percent of your maximum heart rate.
The better conditioned you are aerobically, the higher the level of intensity. Many individuals, however, erroneously believe that in order to promote the greatest loss of body fat, they should perform aerobic exercise at low levels of intensity.
Regardless of how fit they are. The theory is that the low-intensity aerobic training will allow the body to use more fat as the energy source, thereby accelerating the loss of body fat.
It is true that a higher proportion of calories burned during low-intensity exercis comes from fat, about 60 percent as opposed to approximately 35 percent from high-intensity programmes, but high-intensity exercise still burns more calories from fat in the final analysis.
Thirty minutes of low-intensity exercise (i.e. 50 percent of maximal exercise capacity) burns approximately 200 calories, and about 120 of those come from fat (60 percent). However, exercising for the same amount of time at a high intensity (i.e. 75 percent of maximal exercise capacity) burns approximately 400 calories.
At the 35 percent fat utilisation figure, the 140 calories burned comes from stored fat.
The more vigorous exercise burns both more total calories and fat calories, but milder exercise has its benefits as well.
For example, many overweigh people find lower-intensity exercise to be more comfortable and, therefore, are more willing to engage in such workouts. And, low-intensity workouts do promote weight and fat loss. You just have to do them for a longer period of time.
Low-intensity exercise, however, is not a better or more effective way to lose weight than more intense physical activity.
The idea of the ‘fat burning zone’ is simply a myth. Keep in mind that you lose more weight and body fat when you expend more calories than you consume, not because you burn fat (or anything else) when you exercise.
Once you decide what training recipe to follow, choosing between the various types of exercise is largely a matter of personal taste.
Keep in mind that your ultimate decision on what exercise mode to adopt should factor in a number of considerations, including the following:
- Do you enjoy performing the activity? If you don’t, you are not likely to stick with it.
- Is the activity orthopedically safe for your body type? For example, the undue stress imposed on your body by jogging may make it an inappropriate choice for you.
- Is an acitivity more or less inclusive, conditioning-wise, than another option? Does it involve several vs. a single component of physical fitness?
- Is the exercise mode convenient? Do you have the resources… a pool, an exercise machine, or whatever… that the activity requires?
- Does the activity provide a challenging, yet sound, workout? Does the nature of the exercise or design of the machine used during the activity preclude you from compromising your efforts?
The point to remember is that ‘all exercise is not equal’. The better able you are to discriminate between activities and exercise machines, the more likely you’ll be able to identify an exercise mode that best meets your weight control needs.
What type of strength training is best?
From a weight-control perspective, strength training serves two purposes. First, it burns calories, although usually not nearly as many as the more traditional forms of aerobic exercise.
Second, it helps you build ana sustain lean muscle mass – the bodily tissue most responsible for the expenditure of calories. As such, strength training plays a critical role in the most difficult aspect of weight control – keeping the weight off once you’ve initially lost it.
Deciding which type of strength training workout is best suited to your needs and purposes are essentially a subjective decision.
All factors considered, a low-rep, high-resistance approach tends to be a better suited for building lean muscle mass. On the other hand, a high-rep, low-resistance protocol will burn more calories.
On a more promising note, several recently conducted studies have found that it is possible to develop high levels of strength while performing high volumes of work at a moderate intensity.
One of the more obvious applications of such an approach to strength training is that individuals would be able to burn a maximum number of calories and build high levels of muscular fitness in the same 15 to 20 minute workout.
Why is exercise safe for weight loss?
Exercise is the only reasonable safe and effective method for increasing caloric expenditure. An individual can expect to burn 200 to 300 calories during a 30-minute bout of moderately intense aerobic exercise.
In addition, strength-training exercise has been shown to help individuals maintain their lean tissue and possibly, their resting metabolic rates.
A survey conducted by the American Diabetics Association revealed that 90% of maintainers (individuals who lose weight and keep it off) exercise on a regular basis, while only approximately one-third of relapsers (individuals who lose weight only to regain it) were physically active.
Rather than simply promoting immediate weight loss, exercise helps to ensure that weight loss is permanent. Finally it is important to remember than exercise can greatly improve your health regardless of its effect on body composition.