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Saturday, February 25, 2012

How to Calculate Your Daily Calorie Needs

There are many complicated calculations available that can be used to estimate one’s daily caloric needs.  The question is:  How reliable are these formulas?  Regardless of the source, or how valid the formula seems to be on paper, all calorie calculations are simply estimates-best guesses if you will.  They can give you a general idea but there are simply too many variables involved to come up with a hard and fast formula for calculating daily caloric intake that can be applied to a majority of people without taking into consideration age, gender, height, amount of lean body mass, hydration, frame size, individual goals and more.  

Some formulas are better than others, naturally, but keep in mind that even the most seemingly scientific formula should serve mainly as a baseline or a starting point from which you can gauge whether your body is really changing and what should be adjusted in your program in order for more fat loss to occur and/or more muscle to be gained.
  Moreover, any “serious” formula must be tied to your body’s energy needs.  Taking your age, sex, frame size, etc. into account, caloric needs are also dependent upon the amount of energy you use during a typical day.  Are you sitting at a desk most of the time?  Chasing a toddler (or two) around? Working out three times per week to stay healthy or running marathons several times a year, logging mile after mile every day of the week?  Each of these levels of activity have different calorie needs from sedentary to extremely active.  Days in which you are not working out (scheduled “off” days or otherwise), require a lot fewer calories while workout days require additional calories. 

The “plus or minus” part of the equation is based on how those calories are manipulated relative to your “basal metabolic rate” or, BMR.  BMR is defined as “the minimum amount of energy (in the form of calories) that your body requires to complete normal functions such as, breathing, digestion, and for heart and brain function. BMR equations can be very inaccurate because they do not take into account body fat percentage such as with very muscular people.  With muscular people, the formula will underestimate calorie needs and in the very fat, the formula will over-estimate calorie needs.  So again, working with these formulas are an inexact science to be sure.  

The baseline to which all adjustments for age, sex, frame size, personal goals and activity level are made begins with your BMR; your “maintenance” level of calories. Calculating BMR uses the variables of height, weight, age and gender.  The only factor it omits is lean body mass vs. your fat mass which varies from person to person and increases with the amount of muscle you have on your body.  Leaner bodies need more calories than those that carry more fat and less muscle. 

In order to keep your body from attaching it's own muscle tissue, a caloric deficit of no more than 10-15% per day would be desirable.  So a woman who has a BMR of 1,352, for example, would need to burn an extra 203 calories per day in order to create a caloric deficit that will result in fat loss but not be so extreme as to cause the body to use it's own muscle as an energy source. One way of creating a caloric deficit is to consume a little less food (the 10-15% deficit) but this can make for slow-going fat loss while calories burned through exercise or a combination of both exercise and good nutrition creates a much faster rate of fat loss.  Best of all, burn calories through exercise, especially the right kind of exercise, and you will burn more overall calories at rest thus increasing that BMR (with every workout.)

Again, there can be a lot of math involved here so why not take a short cut?  Go to any store that sells house wares and buy a bathroom scale that measures body fat.  Tanita brand makes many models, some of which are very reasonably priced and the body fat measures are surprisingly accurate, especially if you consider the level of accuracy that most of these mathematical formulas are based on.  Once you know what your BMR is, you can begin charting the calorie content of everything you eat for a couple of weeks until you know, visually, what the portion sizes look like that correspond to the number of calories you are allotted at a given meal in order to stay within your maintenance level (BMR.)  Keep in mind that although you might know how many calories to consume on a given day, you still have to figure out what to eat-and that’s a whole other issue.

The more fat you have on your body, the faster it tends to come off-and the more you can lose without slowing down your metabolism. A good rule of thumb? Eat for the body you want, not the body you have.

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