This is probably stupid but here goes: I know that it takes a 3500 calorie deficit to lose a pound but how many calories does it take to actually gain a pound of fat? Common sense says 3500 but I'm curious.
3500 calories = 1 pound of fat to gain and to lose.
That is at least what the books say, but sometimes I don't believe it only because I can have a hard time seeing the difference between fat weight and water weight during a weigh in.
Last edited by tater tash; 09-12-2008 at 07:03 PM.
If I eat more than I should, I'm not only adding more calories but am also adding more sodium to my diet. So I could eat 3500 calories and gain a pound of fat, but I might also gain a couple of pounds of excess water weight. That might explain it
but If I eat 10 calories over plan...I gain a pound...
But is it a pound of fat? No.
Water weight from sodium, normal daily fluctuations in our weight, if there is food or matter still in our digestive systems, etc. ... all of those things influence what you weigh.
But unless you eat 3500 cals, you haven't gained a pound of fat.
It's stated this way: 1 pound of fat contains 3500 calories.
When you gain and lose weight, you may or may not be gaining or losing fat.
If you burn 3500 calories, some of those calories will be from carbohydrate (from muscle and liver stores of the compound glycogen), some may be from protein (because it can also serve as fuel), and some from fat.
There's a lot more going on in the body than burning calories. For example, protein is needed to repair muscle, connective tissues, skin... you name it. Fats are needed by all cells for cell membranes, and cholesterol is an important component of cell membranes. Also for skin oils, cushioning around organs, etc. Carbohydrates are mostly used for energy, and most of that goes to feed the brain. Only muscles burn substantial amounts of fat for fuel.
And that is partly why if you burn 3500 calories more than you eat in a week, you should lose a pound a week on average--but that doesn't mean it will happen every week like that.
The unknown part of the equation is how many calories your body is using. If you eat 3500 calories every day, you will not gain one pound per day, because your metabolism is never at zero - but how many calories does your body burn each day, and what factors affect how much you're burning?
If anyone were to develop a precise, yet easy and inexpensive way of measuring metabolism, they would no doubt, win the Nobel prize, and would get very, very rich.
Arthur C. Clarke actually wrote a "law" that says: Any sufficiently advanced technology is indistinguishable from magic.
I think that works for our biology too. It's a pretty darned advanced system packed into these things we call bodies. And it's so complex and so advanced that a lot of times it seems mysterious and magical.
There are ways to medically test someone's resting metabolic rate and basal metabolic rate. They are really just snapshots of a particular point in time. There are also ways to estimate these based on age, gender, and size--but often people who are obese or have been obese have lower metabolic rates than those who have never been obese.
The only way to get some kind of handle on it is trial and error. FitDay will give you an estimate of your daily calorie burn, but most people on 3FC have found that it reads high. So, I've set FitDay for essentially totally sedentary, and that seems to work. (I add exercise that I do, but not things like daily housework.) And then I try to meet the calorie deficit that will bring about weight loss, but without going below 1200 on average. Sometimes that means I'll lose slower than I'd like, but that's just the way it is!
The other issue is our bodies reaction to losing weight. As a species, we are designed to maintain weight...protecting against famine. When our bodies get less calories than they need, the metabolism slows down to make sure we don't starve to death. (This is why folks can live on starvation diets for longer periods of time than you would guess.) When our bodies think we have been calorie deprived, and then we give it some excess, it "gloms on" to those calories just in case food will be short again.
So, from a strictly mathematical point of view 3500 calories is a pound of fat, gaining or losing. However, a calorie is actually a measurement of the energy it takes to heat something. I got this definition off the web "A unit measuring the energy value of foods, calibrated by the quantity of heat required to raise the temperature of 1 gram of water by one degree celsius at a pressure of one atmosphere."
Since our metabolisms are not robotic, but "smart machines" (who don't necessarily share the same goals that our minds do) the calorie counting and metabolism measuring we do is all a guesstimate! Each person burns calories differently, and if I understand correctly, our burn rate (metabolism) changes constantly. Which is why exercise is so necessary...it increases the burn rate. Fat doesn't burn any calories to maintain, muscle tissue burns calorie even when you are at rest.
Also, when you lose weight too fast on an unhealthy diet, without exercise, you lose muscle. Then you gain back fat without exercising. Cycle repeats over and over. Then your metabolism is lower just because you've lost muscle.
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