Diet

Hi,
Just did a google search and the suggestion seemed to be that as 1 pound of fat contains 3500kcal, to loose one pound you need a deficit of 3500kcal. Is this correct? I'm not talking about some of the complex issues, but this seems to assume that roughly consuming 1 pound of fat which is on your body is the same as consuming 3500kcal of food. I had assumed that there might be large energy costs in extracting energy from food and that shit must have calories in it.

So, is there a rough one-to-one correspondence between food kcal and on-body kcal, or is there a rough multiplier?

Thanks.

David Coley wrote:Hi, Just did a google search and the suggestion seemed to be that as 1 pound of fat contains 3500kcal, to loose one pound you need a deficit of 3500kcal. This this correct? I'm not talking about some of the complex issues, but this seems to assume that roughly consuming 1 pound of fat which is on your body is the same as consuming 1 pound of food. I had assumed that there might be large energy costs in extracting energy from food and that shit must have calories in it. So, is there a rough one-to-one correspondence between food kcal and on-body kcal, or is there a rough multiplier? Thanks.

The short answer is: emphatically, no. The calorie system is a gross oversimplification of thermodynamics and metabolism that was developed by chemists burning sh!t and measuring how much hotter a cup of water gets. It does correlate fairly well and so is still a useful system (if you're in a calorie deficit, you will lose weight), but due to the fact that everyone's body systems are different, YMMV.

FrankPS wrote: I think it is more accurate to say "one pound of weight," rather than a pound of "fat."

Ted
Any idea what the multiplier might be?

I would suspect that it would vary from individual to individual. Not sure if this has ever been studied, but I'd imagine one could self-monitor to estimate it. It definitely would not be a simple 1:1 ratio, though. Factors such as absorbance (not all of the calories one consumed are even absorbed), loss through thermal pollution, variability in metabolic efficiency, etc make it difficult to predict consistently. This article does a nice breakdown of the issues:
authoritynutrition.com/debu…

David Coley wrote:Hi, Just did a google search and the suggestion seemed to be that as 1 pound of fat contains 3500kcal, to loose one pound you need a deficit of 3500kcal. Is this correct?

David Coley wrote:I'm not talking about some of the complex issues, but this seems to assume that roughly consuming 1 pound of fat which is on your body is the same as consuming 1 pound of food.

Eric Carlos wrote: Incorrect. I can loose a pound of weight just by taking a dump.

divnamite wrote: No. 1 pound of lettuce doesn't have 3,500 cals.

One reason this is of interest in climbing, is whether carrying kcals on your body is more efficient than in your backpack.

It's kinda weird that 16 oz of olive oil, for example, is actually over 4K calories. So the 3500 rule is hard to apply even in with a pure fat.

Jon Frisby wrote:It's kinda weird that 16 oz of olive oil, for example, is actually over 4K calories. So the 3500 rule is hard to apply even in with a pure fat.

good point on both counts

So, anyone got any idea of the multiplier?
It has to >1, but that is all 1 can figure out. I understand an exact answer is impossible, but is it 1.1 or 3?

The page below gives 2 references supporting 2 numbers: 1.15 and 1.39. In order to decide this kind of question, I would also need

1 - metabolic cost of supporting 1 lb of fat, per day
2 - relative efficiency of carrying on the body vs in the pack
3 - fraction of time/ travel/... with/without food stores in pack
4 - the confidence that after porking myself up for a couple of months, I would cheerfully subsist on a starvation diet

I expect the numbers to show that item #4 is the critical factor.

zoeharcombe.com/standalone/1lb-does-not-equal-500-calories

Pretty sure aleks would recommend a steady diet of fish heads and cheesesteaks. Many a bold flash have been a direct result of this diet.

Latro wrote:The page below gives 2 references supporting 2 numbers: .....

1. The only thing that actually “detoxes” you is your liver.

2.  Everything is a chemical, including your detox tea.

David raises an interesting question everyone seems to be missing.....

Say you are doing a wall or alpine climb, is it more efficient to put on a couple of extra fat pounds before the climb with the concept that it's easier to carry than the same weight of food in the haul bag.

Two extra pounds on the body (fat cals) = 7,000 useable calories while climbing you don't have to stop to consume.

The problem I would think is the conversion rate, can you burn the fat cals efficiently while climbing and carry less food? 

A pound of fat at 3,500 cals weighs a pound. But a pound of candy bars might be 10,000 cals for example. 

Another thing to ponder would be burning fat cals might keep you going at a carried weight savings but if your body is screaming for carbs you'll cramp up.

John Barritt wrote:

David raises an interesting question everyone seems to be missing.....

Say you are doing a wall or alpine climb, is it more efficient to put on a couple of extra fat pounds before the climb with the concept that it's easier to carry than the same weight of food in the haul bag.

Two extra pounds on the body (fat cals) = 7,000 useable calories while climbing you don't have to stop to consume.

The problem I would think is the conversion rate, can you burn the fat cals efficiently while climbing and carry less food? 

A pound of fat at 3,500 cals weighs a pound. But a pound of candy bars might be 10,000 cals for example. 

Another thing to ponder would be burning fat cals might keep you going at a carried weight savings but if your body is screaming for carbs you'll cramp up.

Most people are not nearly fat-adapted enough to do this efficiently. I've heard of numbers in the 30-40% range in terms of the usable fuel from body fat / energy availability

+1 on what Jon said!

Also the calorie is not really as relevant of a diet tool as we assume. It was created during a time when americans were chronically underweight as a means to make sure us GIs were eating enough in basic training I think. So now it has little use for the situation where most americans are overweight. Not all calories are the same, your body uses a calorie from veggies very differently than a calorie from sugar. I personally don't pay any attention to calories at all. Instead I am more interested in sodium and sugar consumption.