SPRINGER: Fitness: Weight loss math flawed

When it comes to losing weight there is one magic number that seems to have prevailed over time: 3,500.

This is the amount of calories it takes to lose one pound. If you restrict your diet by 500 calories a day over the course of a week, the scale should, according to the math, read one pound lighter.

This is not always the case. There are many variables that play a part when it comes to losing weight.

Let's examine why you might be doing your math correctly but the scale is refusing to budge.

Joseph Donnelly, director of the Energy Balance Laboratory at the University of Kansas, has studied weight loss with regard to caloric intake and expenditure.

Donnelly notes that the math of losing weight "is fundamentally flawed in that it assumes two things. One, that the components of energy intake and energy expenditure are static; and two, that they do not interact."

Unless you are living in a bubble at a research lab, your calories in and calories out will vary, sometimes drastically, each day.

The only way to perfectly control the calories you take in is to eat nothing but prepared, packaged, exact servings of food. This is a very narrow and boring way to live and eat. Go out to eat once and you have blown the tab for the day, since preparation and portion size vary widely at restaurants.

Calories out can vary also due to resting metabolism, exercise, lifestyle activity and even the thermic effect of food, and how all of these interact with one another.

Different foods require more calories to break down and digest, hence the thermic effect.

The timing of your food intake can also affect energy expenditure: going too long between meals can depress your metabolism, so that the same number of calories now results in a different outcome. Plus, eating directly before going to sleep in the evening might also cause those calories to digest slower or be stored as fat.

The best way to accomplish a calorie deficit of 3,500 calories each week is to combine diet modification with exercise. So, cut back approximately 250 calories a day from your diet while burning off an additional 250 through exercise. This is the easiest way to diet without feeling deprived or stuck at the gym forever.

Even if you are able to accomplish this deficit, it does not mean that you have successfully lost one pound of fat. Most of the weight lost at the beginning of a diet program is either water and/or muscle.

Also, if you are pretty conscious about your eating and exercise habits, your body might be less likely to give up those extra couple of pounds.

All of this "diet math" is not meant to discourage you from a weight loss attempt but to inform you that all calories are not equal. The 3,500 calorie equation should be used as a rough guideline, otherwise the results can be discouraging if you do not get what you expect.

Instead of focusing on your exact calorie intake or expenditure, put your energy toward eating well and staying active. These are two principles that will never let you down.

Kim Springer and her husband, Mike, are Certified Personal Trainers and owners of Springer Training. They can be reached at 233-9442 or at their Web site www.springertraining.com.


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