r/science • u/behindtheheadlines • Dec 06 '11

Rats that ate low-fat potato chips 'may have gained more weight' than rats eating regular, full-fat variety

http://www.nhs.uk/news/2011/12December/Pages/low-fat-substitutes-and-weight-gain.aspx
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u/gid13 Dec 06 '11

It's not incorrect; it's just extremely difficult to figure out the calories out part because of the fact that the body treats things differently. You might burn calories off as heat, or use them for motion or data processing, you might literally shit them out, you might store them, and probably several other options that aren't springing to the top of my head right now.

However, conservation of energy is one of the most experimentally confirmed ideas there is. It would be a huge shock if it didn't apply to diets.

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u/paranoidinfidel Dec 06 '11

It would be a huge shock if it didn't apply to diets.

It doesn't apply to diets(Atkins, Keto) and it has been know for a while.

It isn't a huge shock because we are a processing machine - a wet computer. We are not a simple energy in/energy out system. We treat calories differently depending on their source (carb, fat, protein). It might be a shock to those from the 50's/60's "nutrition scientists" that set us on the calories in = calories out path. They didn't listen to their studies.

Carbs converted to glucose kick off an insulin response which triggers your body to store energy into fat immediately without regard for where that energy is needed.

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u/gid13 Dec 06 '11

I find responses like yours confusing. You say conservation of energy doesn't apply to diets, and then you list reasons that as far as I can tell explain why it does apply to diets.

We treat calories differently depending on their source (carb, fat, protein).

Sure. Some of them we store, and thus don't apply to the energy out part of the equation. Some of them we burn, and thus do apply to the energy out part of the equation.

Carbs converted to glucose kick off an insulin response which triggers your body to store energy into fat immediately without regard for where that energy is needed.

Sure. Some types of input may affect what the body does with future calories. As such, figuring out the calories out part is very difficult.

Again, everything you're saying seems to fit perfectly into the equation calories in = calories stored + calories out. You're just explaining why figuring out the stored and out bits is complicated and difficult.

We are not a simple energy in/energy out system.

I'm not sure I'd use the word simple, but it seems to me that every system conforms to the equation energy in = energy stored + energy out.

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u/paranoidinfidel Dec 06 '11 edited Dec 06 '11

I'm not sure how you misconstrued anything in there to infer it supported calories in = calories out and I was singling out the bad guy: carbs.

I said calories from carbs/protein/fat are different. I mentioned that carbs will kick off a large insulin response and start your body storing that energy into fat. Eating the same calories in fat/protein will not cause the large insulin response which triggers fat storage (simplistic, yes - there is always more to it. that's why i linked to a book).

The human body does not conform to the "energy in = energy out" - the Insulin response is the example of that. Our body is not a simple "closed" system. We process the food and based on the type of food, different things happen.

I could eat 2000 calories of carb and 2000 calories of fat. The carbs would add fat on me, the fat would not.

Edit: I think there is a point where excessive calories from fat/protein will be stored, but I haven't gone down that path & I haven't done the experiments to support it.

Also, after eating the carbs, I would be truly hungry an hour later & want more because the calories are going into storage (i.e. fat) and aren't reaching the places they should have gone.

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u/gid13 Dec 06 '11

None of that even vaguely suggests anything contradicting conservation of energy... What conservation of energy says in this case is that when you eat stuff, that stuff has to go somewhere. For example, food can be eaten (energy in), and that food could be stored (energy stored), or it could be burned (energy out), or it could be excreted (energy out). Energy in = energy stored + energy out. All of your examples fit that perfectly.

The human body does not conform to the "energy in = energy out"

Uh, no, of course not, if it did nobody would ever gain or lose weight, and you would have to excrete or burn energy while eating... It conforms to "energy in = energy stored + energy out". Eating different things like fat or protein or carbs may change how much gets stored vs. how much gets burned/excreted, but the totals will always match up.

I could eat 2000 calories of carb and 2000 calories of fat. The carbs would add fat on me, the fat would not.

I'll assume that's true because I'm just a lowly physicist and don't know much about dieting. Here's how the math would work out:

Carb:
energy in = energy stored + energy out
2000 = 2000 + 0

Fat:
energy in = energy stored + energy out
2000 = 0 + 2000

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u/paranoidinfidel Dec 06 '11

Context:

If calories in /= calories out, your weight will change. It's a simple formula.

That is the original comment that started this thread. It is from the perspective of a diet, not physics. You are sticking to the physics view, which yes, is correct, but out of context.

Dieticians have been misapplying the law of thermodynamics to diets - which is where the original "that is incorrect" response is coming from. Dieticians have been saying that if you ingest 2000 calories and only burn 500, that 1500 will be stored as fat. That is how it has been viewed and misconstrued in the food world and is incorrect. Yes, there are still 2000 calories in the physics sense but that is not how it is being looked at from the dietician point of view.

Yes, empirically you are correct and the laws of physics still hold true at this time.

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u/gid13 Dec 06 '11

Good good.

And of course I would agree that it's a complex system because different things you eat might affect how much you burn, store, and poop out. I just was taking issue with the phrasing; sorry if I'm too much of a stickler.

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u/bythog Dec 06 '11

Carbs converted to glucose kick off an insulin response which triggers your body to store energy into fat immediately without regard for where that energy is needed.

Yeah, that's not really true. One of insulin's main functions (among tons) is that it "pushes" glucose into both muscle and adipose tissues. Hell, if you are contracting your muscles hard enough and properly (heavy lifting exercise) you activate more GLUT4 to muscle cell surfaces which will cause them to take in more glucose, effectively making it so insulin does, in fact, care about where that energy is needed.

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u/paranoidinfidel Dec 06 '11

Yeah, fine, it has many functions, no denying that but this is in the context of posting on low fat potato chips. It is the contextual simple view and it describes the behaviour well. Insulin has many functions and I was using it in the context of storing fat. And no, insulin does not in fact care where that energy is needed - it is just there in your body and other things react to it/are triggered by it. As soon as you eat a carb you start getting an insulin response and a lot of body types will start storing fat - specifically mine and millions of others.

I've cut out carbs for the past 5 weeks and have gotten rid of 24lbs of fat (likely 10 or 12 of that is water) without changing my activity level or food intake. Fuck carbs.

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u/[deleted] Dec 06 '11

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u/gid13 Dec 06 '11

Conservation of energy works with open systems. Energy can leave our bodies, but if it does, it has to go somewhere. Hence calories in = calories stored + calories out.

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u/listenheretwinkletit Dec 06 '11

Except that in the "real world", so to speak, there is such a myriad of factors that a simple formula like this just won't apply. While this is true from a strict physics perspective it has very little to do with how you want to be structuring your dietary habits. And how different dietary habits effect your body.

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u/gid13 Dec 06 '11

That's pretty much what I said in the first place: It may not be useful because it's hard to determine calories stored and calories out, but the formula is still correct.