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If you want to see your personal statistics -- your BMI (basal metabolic index), BMR (basal metabolic rate), RMR (resting metabolic rate), your body fat percentage, how many calories you require daily, how many calories you burn per day and per week from exercise, and how much more or less food (calories) and exercise you need to have to gain or lose weight, as well as additional information, please fill out the Form and submit it.
Many sources are extremely misleading about the number of calories burned during exercise, especially low-intensity exercise. If you use a total of 300 calories of energy in an hour, while exercising, you have not burned 300 "extra" calories, because your basal metabolism is responsible for part of the calories used. In other words, if you weigh 150 pounds, you would have burned @135 of those 300 calories sitting in a chair reading a book. The useful number for weight loss is the calories burned by the exercise — that is, total calories used in excess of RMR calories for the period. In our example, that would be 165 calories, not 300.
Even more troubling are several empirical studies that show little or no additional weight loss from moderate walking, by groups of women on low-fat low-calories diets.
People who like mathematics will immediately understand why, as the intensity of exercise increases, weight loss from exercise increases faster than the exercise intensity: there is an increase in the proportion of calories burned by exercise to calories burned by BMR. (Also, the slight RMR increase following exercise increases with intensity.) The weight loss from an hour of exercise at Intensity 4 (4 calories per pound per hour) is more than double the weight loss at Intensity 2. This is one factor in weight gain with age: as the body gets older, it takes more effort (or becomes impossible) to maintain exercise intensity.
There is good news, as promised: you can lose weight by exercising. The key is intensity. If you double your walking speed — say you cover two miles on a half-hour walk instead of one mile — your will lose three to four times as much weight! In practice, although the slower walk has health benefits, some reputable studies show that you can expect to lose almost no weight at all.
Where Do Calories Go?
Between 20 to 50 percent of your daily caloric needs are determined by physical activity. The remainder are burned through basic body functions such as breathing, circulating blood, and fueling/destroying/replacing your 100,000,000,000,000 cells.
Most people assume that their brain uses few calories, since it has no moving parts. Actually, your brain uses about 18-25% of your basal food requirement. Remarkably, its rate of consumption remains almost constant. Whether you are sleeping, watching Montel Williams or a Hallmark movie on television, taking the SAT's, or playing WoW, your brain is using calories at pretty much the same rate.
If you want a more accurate BMI, we recommend the Omron 306C. This little handheld device is quite accurate. It gives BMI and body fat % figures, based on impedance, and is downright cheap for a device of its accuracy. It's available from Amazon.com for $25.99. (If you want one, please use our link -- it won't cost any more and will give us a tiny bit of income to help defray server costs.)