I read somewhere once, that the less you weigh the less calories you burn. So as I get smaller I would have to work harder to lose the same amount of calories. I was just wondering if that was true.

Yes it's true. Think about cars: the larger/heavier a vehicle is, the more gas it takes to go the same distance than a smaller/lighter car, assuming the engine, etc. is the same. The heavier something is, the more fuel it takes to operate it.

But, don't let that discourage you. The smaller you are, the less you have to lose. If you think about it as a proportion rather than an absolute number, it helps. If running 30 minutes when you are 200 pounds burns X% of your calories, then running 30 minutes when you are 150 still burns X% of your calories. That is a large generalization, but it's a helpful model to think about.

The other thing to know is that different tissues in your body require different amounts of fuel. Fat is the least metabolically active tissue, so it takes fewer calories to sustain it than your organs or muscles, for example. So, as you lose fat, the % of your weight taken up by fat decreases, and that gives you a slightly higher burn rate per pound, so to speak. For example, if a pair of identical twins had different body compositions but weighed the same, the one with the lower fat / higher muscle ratio would need MORE calories than the other with the higher fat / lower muscle ratio. The difference isn't huge, but it's there. This is one reason strength training is so important -- if you increase your muscle mass, you boost your metabolic rate and you'll burn more calories than if you simply lost fat but did not add any muscle. In addition, one reason crash diets are so metabolically harmful is that the extremely low calories cause you to LOSE muscle along with fat. Low-carb diets can have this effect, as well.

Very well put, funniegrrl.

That does make sense. Thanks so much for the input.

http://www.healthonecancer.net/HC_CalBurned.asp

The above link goes to a health calculator that you can put in your weight and activity and it shows calories burned.

We have some calculators on site in our Fitness section

On the "Work it Off" page, you can enter your weight, and choose an activity, and the number of minutes you exercise, and it shows how many calories you burn. You can enter different weights to see how it compares. For example, if you weigh 120 calores and do 20 minutes of low impact step aerobics, you burn around 127 calories. A person weighing 180 calories would burn 191 calories. Or course all of these calculators, no matter where you get them, are based on estimates, and your own experience will be unique. But its an interesting way to see how our energy expenditure can change.

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