With all of the talk lately of loosing some serious pounds, here is my soft rant on losing weight. Bottom line, losing weight takes a lot of time and effort. Here it is, by the numbers.
First, a pound of fat contains 3,500 calories. This means to lose 1 pound of fat, you need to consume 3,500 less calories than you burn. For this example, let’s assume you are trying to loose 2.5 pounds per week or 10 pounds per month–a differential of 7,000 calories.
Next, a male needs to eat 1,500-1,800 calories per day. (The bigger you are, the higher the base number.) Any less, and you screw up your body’s metabolism, actually making weight loss more difficult.
Finally, a 55-year-old, 6’0" male, weighing 280lbs, doing nothing at all but sitting around, will burn approximately 3000 calories, just by living. (Note: The smaller you are, the lower the sedentary burn rate. The same male weighing 180lbs will only only burn 2400 calories.)
Put all of this together, and, in order for our 280lb man to loose 2.5 pounds per week, he can eat no more than 1,750 calories per day, pretty close to the bare minimum for someone of his size. This would be impossible for our 180lb man, as he would only be able to consume 1,150 calories per day.
So, for our 280lb man to lose more than 2.5 pounds per week, he must add exercise to the equation. The good news is that the bigger you are, the more calories you burn by doing something, anything. If our subject was to walk 2.5 mph for 60 minutes, he would burn 380 calories. Still a tall order, though–to loose another pound a week, he would need to walk for 9.2 hours during the week. If he were healthy enough to increase his pace to 3.5mph, a brisk walk, he is now up to 500 calories/hour, or 7 hours of walking to loose that extra pound.
The numbers for a couple of other exercises–
- Swimming laps, freestyle, moderate pace: 1050 calories/hour; 3.3 hours for a pound
- Bicycling, 10-12mph: 890 calories/hour; 4 hours f
