Week 10 - Know your numbers....

It seems that every few years the pendulum swings wildly when it comes to counting calories -- new diets come and go touting everything from strict measuring and weighing of food, to knowing the caloric content of every single item that passes your lips, to burning off a certain number of calories through exercise.  At the other end of the spectrum comes the recommendation to disregard calories altogether -- that as long as you're eating "clean" foods in just the right combinations of carbs, proteins, and fats, calories don't matter at all.  In other words, eat correctly and the calories will take care of themselves.  While both approaches may work for some people, the truth lies somewhere in the middle for most of us.

The reality is, calories do matter.  The human body is a highly complex machine with an amazing ability to adjust to fluctuations in nutritional intake.  But like any machine, it obeys certain laws of physics that just can't be avoided, and the way it utilizes and stores energy is no exception.  Calories matter because the human body only needs so much energy on any given day to perform all of its necessary functions.  We take in a certain number of calories through the foods and beverages we consume. Our bodies do one of two things with those calories:  either they are used immediately for energy, or if not needed at the moment, they are stored as fat.  This law of thermodynamics is quite simple -- eat too many calories and you will gain weight.  Eat too few calories and you will lose weight.  So, if it's that easy, why so much controversy surrounding calorie counting?

To answer that question, we must first understand what calories are. A calorie is not a tangible thing; rather it is a unit of measurement of the amount of energy required to raise the temperature of 1 gram of water 1 degree centigrade.  Huh?  Let's just simplify things by saying that different foods contain different amounts of energy within their structure, and this energy is measured in calories.  A medium apple contains about 100 calories.  A small square of chocolate also contains about 100 calories.  Both foods contain the same amount of energy for our bodies to use.

Counting calories can be quite tedious.  It requires knowledge of (or access to) an exhaustive list of the caloric content of foods.  It requires becoming familiar with exact portion sizes so caloric estimates will be accurate.  It means constantly thinking about every morsel that passes your lips which can diminish the joy of eating.  Counting calories involves scales, measuring cups, and mathematics.  And since most calorie counting is associated with "dieting," it can be downright depressing to have only a relatively small number allowed per day.  Ask anyone who has ever tried to stay on a 1,200 calorie-per-day diet for very long -- it's miserable!

But, to just forget about counting calories because it's too much work can be a huge mistake.  It is very helpful to know approximately how many calories your body burns in a day; in other words, how much energy your body is using up in relation to how much energy you are taking in.  In this way, we can learn the optimal amount of food we should be eating to meet our daily nutritional requirements, prevent excessive weight gain or loss, and maintain a healthy body weight.

The average American male needs around 2,700 calories per day to maintain his weight and the average American female needs around 2,000 calories.  These are only averages; age, activity level, metabolism and genetics all play a role in determining caloric requirements but this is a good starting point for most people.  Keep in mind that the more active you are, the more calories your body needs.  The American Heart Association suggests these calorie levels for most individuals:

		Activity Level and Estimated Calories Burned
Gender	Age (years)	Sedentary1	Moderately Active2	Active3
Female	19–30  31–50  51+	2,000  1,800  1,600	2,000-2,200  2,000  1,800	2,400  2,200  2,000-2,200
Male	19–30  31–50  51+	2,400  2,200  2,000	2,600-2,800  2,400-2,600  2,200-2,400	3,000  2,800-3,000  2,400-2,800

¹  Sedentary means you have a lifestyle that includes only the light physical activity associated with typical day-to-day life.
²  Moderately active means you have a lifestyle that includes physical activity equivalent to walking about 1.5 to 3 miles per day at 3 to 4 miles per hour, in addition to the light physical activity associated with typical day-to-day life.
³  Active means you have a lifestyle that includes physical activity equivalent to walking more than 3 miles per day at 3 to 4 miles per hour, in addition to the light physical activity associated with typical day-to-day life.

These levels are determined by first taking into consideration one's basal metabolic rate (BMR) -- the amount of calories required by your body just to be alive.  Imagine sitting in a chair all day and not moving at all -- no standing, walking, moving, or anything else.  Your BMR is the amount of calories needed by all of your body systems to function at total rest -- your brain, organs, digestion, respiration, circulation, temperature regulation, immune system, etc.  When you begin to add in any activity, even something as minor as standing up, the caloric demand goes up.  Normal daily walking, household chores, exercise, gardening, lifting and carrying, etc. drive the caloric demand way up above the BMR.  By knowing your BMR and then determining the amount of activity you get on most days, it is easy to come up with a fairly accurate number of calories needed per day.  This number is your total daily energy expenditure (TDEE).

There are many different ways to calculate your BMR and TDEE including the Harris-Benedict formula, the Katch McArdle formula* or the more precise method of gas analysis which requires going to a testing facility with specialized equipment. Click here for an easy-to-use BMR calculator. Once you know your BMR, you can calculate the amount of activity you get each day by using an activity calculator such as the one at Fitness Partner.  Add your BMR together with your total estimated daily activity to come up with the amount of calories needed to maintain your weight (TDEE).  While not completely accurate, an even easier method for determining daily caloric need is:

   For fat loss:  multiply 12-13 calories per pound of bodyweight
   For maintenance:  multiply 15-16 calories per pound of bodyweight
   For weight gain:  multiply 18-20 calories per pound of bodyweight

You can play around with the different formulas but in the end you will see that they all yield very similar results.

Are you interested in losing weight?  Since there are 3,500 calories in one pound of fat, you must reduce your total caloric intake by 3,500 calories per week in order to lose a pound.  This conveniently works out to 500 calories per day which can easily be accomplished by trimming only 250 calories from what you eat as well as burning an additional 250 calories through exercise.  Sounds simple enough, right?  Unfortunately, studies show that Americans grossly underestimate the amount of calories they are eating in a day!  The good news, however, is studies also show that most people tend to eat the same foods over and over.  Once you learn the basic caloric values for these favorite foods it becomes much easier to meet your nutritional and bodyweight goals.  Dining out can present a significant challenge because it is often difficult to estimate the number of calories in a meal that someone else prepared.  More and more restaurants are including nutritional information for their menu items and many even publish the information on their websites.  For an eye-opening look at just how many calories some restaurant meals contain, check out the Worst Restaurant Meals Slideshow.  Once you realize that some of these meals contain an entire day's worth of calories, you may begin to rethink your dining choices!

This week, your task is twofold:  to determine your basic daily caloric needs using the formulas or AHA table above, and to begin learning the caloric values of some of your favorite foods.  A good place to start is at Calorie Count.  The site is completely free and offers a wealth of nutritional information as well as online community support.  At this point, we are not interested in counting every calorie down to the last morsel, but rather gaining a general sense of the amount of calories in most of the foods we eat and determining whether certain foods are actually worth the "tradeoff" -- realizing that it takes a 45-minute bike ride to burn off a single brownie just may have you reaching for the apple instead!

In future posts we will be examining calories more closely and coming up with strategies to stretch our calories further -- eating foods that are more nutrient-dense so we stay full longer.  We will investigate "empty" calories in junk food vs. "filling" calories in healthy foods.  For now, get in the habit of reading food nutrition labels and sticking with correct portion sizes. We are building awareness of the delicate energy in/energy out balance under which our bodies operate and this will be very helpful in the future as we restructure our eating habits for optimal health.  Pay particular attention to the number of calories in the healthy breakfasts you are already eating as well as your healthy snack.

For a really neat site that allows you to easily compare foods you are considering eating, check out two foods.  It just may help you make a healthier choice!

* For more information on these formulas:
Harris-Benedict Formula
Katch McArdle Formula