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So, yes and no. That's why I said "primarily." It's wayyyyy more complicated than calories-in vs calories-out. But 90% of it does come down to that. More import
by silviogutierrez 7y ago
So, yes and no. That's why I said "primarily." It's wayyyyy more complicated than calories-in vs calories-out. But 90% of it does come down to that. More importantly though, you need to define what "calories-in" means.
I like to think of a silly extreme. If I drink a gallon of gasoline, I've technically consumed what, a billion calories? But I won't gain a single gram.[1] Why? There's no metabolic pathway to convert gasoline to ATP.
If you take that silly example and moderate it, you can see how different factors, including genetics, gut flora, adaptation, etc could affect what is even processed and thus part of the "in" variable.
More concrete, well known examples:
- If you consume 5000 calories of just protein, the metabolic pathway to convert to lipids is extremely inefficient. You will mostly excrete the excess.
- Similar with pure ethanol. If you drank just alcohol (and nothing else), there is no metabolic pathway to convert this to fat.
- Even carbs. If you just ate 5000 calories of pure carbs, de novo lipogenesis (metabolic pathway for carbs -> fat) is rather inefficient. You will gain weight but less than the 5000 - expenditure. A lot of it is burnt off as heat.
- Sadly, for ketoers: the dietary fat to lipid pathway is extremely efficient. Almost 90% of excess will be stored as fat.[2]
See a pattern here? The reality of the typical diet is that we don't just eat one macronutrient. We mix them. And specific ratios are what make food hyper palatable and thus so easy to overeat. Once you start mixing things up, it basically - and I mean basically - comes down to calories in vs calories out.
[1] In fact, I would likely die.
[2] As another commenter mentioned, there was one guy who just ate fat and well in excess of his BMR and apparently lost weight. I'm skeptical, but could believe it simply because it follows the trend: consuming just one can "bend" the rules.
- adamgluck 7y agoWould be curious about the evidence you have that dietary fat is stored as (noticeable) body fat? 70% of the body is fat. Specifically, what evidence is there that dietary fat stored in a way that makes it so that it appears as noticeable body fat and causes meaningful weight gain?
- silviogutierrez 7y agoThis is a great read: https://bodyrecomposition.com/fat-loss/how-we-get-fat.html/ https://bodyrecomposition.com/fat-loss/how-we-get-fat.html/ Never mind the clickbait-ey domain. Lyle McDonald is a nutrition authority and well respected. Though on forums he’s self-admittedly volatile.
- masonic 7y agoLyle's (science) problem is that he runs with every new paper, ignoring the fact that it directly contradicts the paper he touted last year. 21 years ago (I mean this literally, I read him then) he was touting on MFW how the discovery of leptin was going to render dieting obsolete in less than a decade. He has a lot of good content, but it's always decisive, even when some is rong.
- silviogutierrez 7y agoFair enough, I think nutritional science is in its nascent stages, so the whole thing is pretty vague and on shaky ground. However, some cursory empirical evidence does back most of his claims around fat gain. At least to my armchair-nutritionist satisfaction. Anecdata, everyone's favorite - I've seen someone gain no weight eating near 100% protein, while way over their TDEE. Kid you not, 4000 kcal of lean protein and mustard. Also morbidly, you've got alcoholics (spirits), also traditionally under weight while consuming far in excess of their TDEE in ethanol (7 kcal per gram). So some of it can be tested in the field!
- masonic 7y agoHe was always big on pure caloric arithmetic, insisting that microbiome, macronutrient ratios, feeding/fasting timing, etc. couldn't possibly matter because no papers he liked said so.
- benibela 7y ago>I like to think of a silly extreme. If I drink a gallon of gasoline, I've technically consumed what, a billion calories? But I won't gain a single gram.[1] Why? There's no metabolic pathway to convert gasoline to ATP. 26579 kcal
- silviogutierrez 7y agoYou did the math!