Calorie math does not add up

Hawtcookies

Okay, so, the general idea is that 3500 calories = one pound, right? And every calorie that you would eat over maintenance would result in a little fat gain, correct?

I've been trying to figure this out myself, by weighing daily and seeing what happens when I eat more calories than maintenance, which tends to happen in the weekend. I log and weigh everything I eat during the week. On the weekend I log most until a certain point, then usually after a few drinks I'm like, eff it, and start guessing. This leads to a minimal amount of calories eaten on that day.

Anyway, usually on a saturday I can easily get to 4k calories. My maintenance is about 1800-2000, depending on how much hiit or jogging I do. Lets assume I'd have eaten 2k calories over maintenance, which would technically be a 2000/3500 = about half a pound weight gain.

The days after a big food day like that are usually 3-5 pounds higher. All water weight. If I restrict sodium it comes off within three days and I'm right back where I was before Saturday. I do not really restrict in the days after either. Or, at least not enough to offset 2k of extra calories anyway. I don't have that wiggle room, being very short. So where did the half a pound of weight that I should have gained go?

Most people say that one day of overeating does not make anyone fat. It takes more days. But still a lot of people also claim that 3500 calories = one pound. So if you'd eat 3500 calories extra on one day, which isn't that hard if you eat calorie dense food, you should still gain that pound, right? Even though it's just one day.

What do you guys think?

jemhh

#1 3500 is not a hard, set in stone number. It is a best estimate to follow. It is impossible to nail down an exact 1 lb = number. Don't expect exactness. Expect close enoughness.

#2 You're not a weight loss/gain woodchipper. You don't insert your effort (food/exercise) and get immediate results shooting back out. Weight loss and fitness are delayed gratification games. Accept it or be disappointed.

yarwell

3500 assumes a certain fat/non-fat mix - 1 lb of pure fat would be over 4000

So if you put on weight with a lower % fat (like replenishing glycogen reserves) it takes fewer calories to add a pound.

Pure glycogen would require closer to 1800 than 3500, and with the added water stored potentially under 1,000.

yirara

My TDEE is quite a bit higher than calculators suggest despite an office job. Calculators give me about 1540, while it's more like 1800. Numbers aren't exactly what calculators say, and you might also digest certain types of food better than other food. I know I have a problem with fat digestion, thus I suppose I don't gain as much weight from 3500kcals worth of dietary fat as others. I guess it's really just: everyone is different.

Duchy82

I would say your maintenance calories are then probably higher over the week than what mfp has you set to and even though you eat those (according to mfp) 2000 cals over at the weekend you are actually not going over your maintenance calories.

To get a bit more scientific: my guess is mfp uses a normal distribution curve to work out the average amount of calories a person of set height, weight and age needs, you may not fit smack bang in the middle of that. Your metabolism may be higher than the average person of your height, weight and age therefore over a week you are burning 2000kcal over what would be considered the average calorie expenditure. Just my thinking don't take this as fact though.