Taking Control of Your Energy Balance Part 2
Caloric maintenance level is the amount of energy you require each day to maintain your current body fat stores. It is important to know this number because fat is deposited on your body when you ingest more energy than you need. Conversely, the only way to lose fat is to take in less energy than your caloric maintenance level requires for an extended period. In theory, there are 3,500 calories of energy in a pound of fat, so a 500-calorie deficit per day should result in the loss of a pound of stored fat in about a week. If you know your caloric maintenance level, you can figure out the best way to set up this deficit.
In the last installment, I explained how to figure out your current caloric maintenance level by trial and error. This requires ingesting the same amount of calories each day for a couple of weeks and pinpointing the amount required to keep your weight from fluctuating. During this experimentation period, it is important to maintain your present activity level (physical activities of daily living and specific physical exercise(s) that you might be doing) because any alteration will affect your caloric needs. Once you determine your caloric maintenance level with energy expenditure held constant, you can adjust intake and/or expenditure accordingly. For example, you can drop your intake 500 calories per day below your caloric maintenance level and expect to lose a pound per week as long as the reduction does not place you at an excessively low level. In this regard, the United States Department of Agriculture provided estimates of caloric needs based on age, gender and physical-activity level in their 2010 Dietary Guidelines for Americans. Generally speaking, adult women require 1,600 to 2,400 while adult men need 2,000 to 3,000. If you cut calories far below these levels, you risk slowing your metabolism and also providing insufficient nutrition for healthy body function.
Another way to set up a caloric deficit once you know your caloric maintenance level is to ingest the amount of calories that would presently maintain your fat stores while increasing the amount of energy you expend. There are two ways to do this by adding exercise to your daily regimen. One is to increase your resting metabolic rate, which is the amount of energy you require each day to maintain vital body functions. This number depends on how much muscle you have on your body, so you can increase it by performing regular weight training. However, the amount of extra calories you burn per pound of added muscle is relatively small and the capacity to increase the amount of muscle you carry is limited. Consequently, chances are this option will not provide a means for you to lose an appreciable amount of body fat in and of itself. It is also important to realize that if you have already been training regularly with weights (i.e., it was a part of the activity level you held constant while determining your caloric maintenance level), there is a high probability you will have already exhausted this avenue for change and will not be able to add more muscle. That said, it is important to train with weights on a regular basis for general health purposes and to at least maintain the amount of muscle you currently have. Failing to do so will result in a gradual reduction in metabolic rate as the years pass and the potential for a progressive increase in fat stores.
Above your resting metabolic rate, daily energy expenditure depends on how active you are. The best way to increase the activity component of daily energy expenditure is by performing aerobic exercise of relatively long duration on a regular basis. For example, if a 175-pound person jogs six miles per hour, he requires 10 times the resting metabolic rate while doing so. This equates to an additional calorie burn of 13 per minute compared to what he would be burning at rest. Nine 30-minute sessions for this person would bring a pound of fat loss assuming the time spent exercising was time that the person had previously spent at rest. However, if it replaces time that had been spent performing some other type of physical activity, only the net difference will apply. Many people don’t realize this and assume that any exercise will set up a caloric deficit. This is not the case. For example, if a 175-pound person replaced the time he had been spending performing various physical activities of daily living (e.g., light household tasks, vacuuming, light gardening and grocery shopping) with walking at a slow speed on a treadmill (e.g., three miles per hour, which requires 3.3 times the resting metabolic rate and equates to three additional calories expended per minute compared to rest), the net difference would be negligible and fat stores would be unaffected. What is more, even if this benign treadmill walking replaced the most benign activity the person did throughout the day (sleep, which requires 0.9 times the resting metabolic rate), it would require over 1,000 minutes of ‘exercise’ just to lose a pound!This article was originally published in New Living Magazine, which can be accessed on-line at www.newliving.com.
