Structuring an Eating Program: Intake Level
The first step in structuring an eating program is to determine how much energy (measured in kilocalories; a.k.a., dietary calories or Calories with a capital "C") you should ingest daily. There are formulae that purportedly estimate caloric requirements, but due to the extreme degree of variability from person to person, such general estimations are often inaccurate. I prefer using a trial-and-error method to determine the current caloric maintenance level (intake required to maintain current body fat level) and them make appropriate adjustments to that amount in accordance with specific objectives (e.g., fat loss, weight gain or weight maintenance). To employ this method, you must first understand the components of energy intake and expenditure. The intake portion of this equation is simple: It's the energy contained in all of the foods you ingest throughout the day. Expenditure, on the other hand, is a function of three variables. The first, basal metabolic rate (BMR), is the energy required for the maintenance of your existence. In other words, if you were to lay in bed and do nothing all day, there would still be a certain amount of energy you'd need to sustain life. The BMR is predominantly determined genetically; however, it is alterable since it depends on how much muscle you have; i.e., the more muscle, the greater your BMR. The second component of energy expenditure is the thermic effect of activity - the energy required to perform all of the tasks above and beyond the BMR that you do throughout your day. The final factor in energy usage is the thermic effect of food - the energy required to digest the foods you ingest.
To use the trial-and-error method to determine your current caloric maintenance level, you must find the point where a constant intake level, maintained for a couple of weeks, will result in the maintenance of your current bodyweight assuming the three variables of expenditure are kept constant. To find your maintenance amount, follow these guidelines: 1) On day one, weigh yourself at a specific time of the day (ideally upon awakening); 2) Ingest the same amount of calories each day for two weeks (choose an amount that you believe would be close to what would be required to sustain your current weight); 3) Keep expenditure constant for the two-week period by: a) not adding any muscle to your body (if only it were that easy!); b) not increasing or decreasing your activity level (includes keeping frequency, duration and intensity of aerobic training constant); and c) not increasing or decreasing the amount of times per day that you eat; 4) On day 15, weigh yourself under the same conditions that you did on the first day. When you have found the daily caloric intake that results in your bodyweight staying the same for the two weeks with expenditure constant, you've found your caloric maintenance level, which is the amount of energy you need to maintain your current amount of body fat given that degree of expenditure. Now, you can make adjustments accordingly. If you are looking to add body fat (as a bodybuilder might in the off-season or a football player when switching from linebacker to defensive tackle), intake should be set above your maintenance level. A similar caloric increment is necessary if you are attempting to add muscle to your body by training with weights. On the other hand, if your current body fat level is where you want it, you would simply continue to ingest that same amount of calories. Finally, for fat loss, you would set up a deficit between intake and expenditure so that reserve fuel stores (fat deposits) are accessed to make up the difference. In this case, given that drastically reduced or dramatically low intake levels can result in the loss of muscle and a slowing of the metabolic rate, this deficit should be mostly a result of expenditure increases accompanied by only moderate intake reduction.
Maximizing expenditure involves using the most energy for each of the components mentioned previously. Adding muscle will increase your BMR thereby increasing expenditure. However, this is a limited avenue for change especially for those who are close to their genetic potential in regards to muscular development. Eating the given amount of calories in smaller, more frequent meals might also help, but this won't add up to enough to make the difference significant. The majority of expenditure increases should come from maximizing the thermic effect of activity. While any activity you do uses energy, aerobic exercise done at the highest intensity you can sustain is the most effective. These high intensity aerobic workouts also cause positive adaptations in your body's oxygen delivery network, increasing your functional capacity and the level at which you can exercise for extended periods. The end result is an increased calorie-burn potential in the future.
By using the trial-and-error method to figure out caloric maintenance level, you can determine the energy intake required, in conjunction with appropriate expenditure, to allow you to meet your body composition goals.
