Nutrition thoughts I wrote up a while ago

[flexagon]

I've been thinking a lot lately about calorie deficits and weight loss.

I was thinking how there's a total contradiction between these two statements:

1) you get 9 calories from a gram of fat, 4 from a gram of protein and 4 from a gram of carbohydrates

2) the body uses protein and lipids to build structural elements (unsaturated fatty acids make great cell walls, doncha know).

So unless I'm reading something wrong, carbs are actually the only thing that's always converted to energy or stored as fat! (By energy, I mean ATP and CP, the stuff that moves muscles). So what's correct is that the body can get that many calories out of the stuff you put in your mouth, IF that stuff is used for energy, which not all of it is. Increase exercise level and I bet you anything the amount of material needed for structural repairs/building goes up... and I bet that's a lot of what "base metabolism" is.

Thoughts?

Comments

[bluechromis.livejournal.com]

Also, I just wanted to add in case they didn't talk about this in NASM, but the whole 9 cal/g fat, 4 per protein or carb measurement was determined in a bomb calorimeter, so it's only good for estimation purposes, and shouldn't be stated as an absolute fact like it so often is.

That said, I've been tracking my calories in vs. out for about 2.5 months now, and my weight-loss is shockingly close to what you'd expect given the numbers. I was really surprised by that.

[flexagon]

That's pretty cool. I'm curious, how do you know your base metabolism? Did you get it measured?

[bluechromis.livejournal.com]

I've had it measured twice, and those measurements pretty much agree with the avg info I found online. I had it measured at my PT session as part of a research study and I had it measured at Bally's. There was about 100 cal difference between the Bally's measurement and the PT measurement, but I think that is due to my thyroid medication being raised quite a bit in between. So I've got my BMR as roughly 1675, and then "lifestyle" cals as 720. With exercise added in, I was averaging a 750 cal deficit, and losing about a pound and a half on average. That's all on average, it IS typically 1.5/wk, but sometimes it's 1 one week, and 2 the next. Over the course of 9 weeks though, that's some interesting consistency.

[flexagon]

Geez, a 750 cal/day deficit. I find it AMAZING that people can do this and still function -- I mean, that's a full meal's worth of food. I know that people do, and don't even necessarily suffer while they do it, so maybe what's really amazing is what a tremendous energy store is actually maintained in the body. If a pound of fat really represents 3500 dietary calories (and again, does it really? because even if it's true, how many calories are burned to get the fat out of the cells?) then it starts to make sense how hard it is to lose weight -- and how long it takes people to starve to death.

[bluechromis.livejournal.com]

I hear what you're saying, because it sounds like a lot, but actually, I don't even notice a 750 cal/day deficit. With that I'm still eating around 2000 cal/day. Some days I'll eat 1400 without noticing hunger, other days I will eat 2500 without feeling gorged. In the past, every structured diet I was put on had me eating 1600 cals/day or less, which is a more than 1000 cal deficit, which I suppose was why I was always so miserable on them - I was starving myself. Trainers did this to me, nutritionists did this to me, I did this to me. What the hell people?

I think the thoughts on 3500 cal/lb are based more on dietary studies and observations than on the specifics of calories involved in burning fat. I'm not positive, but I think I remember reading about that a while back.