We often hear the word “metabolism” tossed around when people discuss weight loss. While metabolism does play a role in what your body does with food, it is simply the process by which your body converts food into energy. The real issue, as has been said here before, is the number of calories entering your body compared to the number of calories being converted into energy to be used by your body. If you take in the same number or more calories than your body uses, you will gain weight or stay the same weight. If you want to lose weight, you must take in less calories than your body uses over the course of the day.
How can you figure out how many calories you use in a day? There are several calculators available to count up all the calories you burn in a day (try this one) but there are also several general guidelines that you can follow.
Body Size: Just as a jet uses more fuel than a four-seater Cessna to cover the same distance, larger bodies need more fuel to do the same amount of work. So, consider your height, weight and bone structure when thinking about calories requirements.
Body Composition: Muscle requires more energy than the same mass of fat, so the more muscle you have, the more calories you will burn. Conversely, the more fat you carry, the more work you must do to lose the same number of calories.
Age: Metabolism rates slow as you age. So those of us in the 55 plus range have an extra challenge. This characteristic is the reason that we can’t eat like we did in earlier years. Our metabolism has slowed so we burn less calories doing the same amount of work.
Gender: Men generally have more lean muscle per pound of weight than women. As a result, they burn more calories because their metabolism is slightly higher.
Location: People in the colder parts of the world tend to need more calories to keep warm than those nearer the equator. This means they can get away with eating a little more than their tropical cousins.
So, apart from using a calorie calculator, you can use the general guidelines listed above for daily calorie needs and adjust them as you see fit. The bottom line is that if you are trying to lose weight and it isn’t working, you need to eat less and/or burn more calories.