Calories vs Fat

Not sure if this would be better suited to GQ, but my hypothetical isn’t very realistic so I doubt there is a real factual answer.

I know that calories in/calories out is the crux of how a body gains, loses, or maintains weight. But where does fat come into it?

For example, let’s say we have two identical twins in perfect health. They live identical lives in identical environments, and expend the exact same amount of calories each day. At their level of activity, they each require 2000 calories per day to maintain their current weight. What happens if they each get 1500 of those calories each day from nutritionally perfect meal replacement bars, but then one of them gets the other 500 calories from eating steamed zucchini, and the other one eats 500 calories of butter? Will they still maintain the same body size?

Yes, in the case of such twins. Not always with different individuals. The “low fat” diet was based upon poor science and inadequate studies.

However, of course the zucchini does has significant fiber, which could change the sitrep.

That’s more than a lb of zucchini, so one of these guys is gonna have a much easier time.

Fat is just a really dense, easily digested source of calories. It’s not magically bad for you in other ways.

Really seriously, the issue isn’t fat - eat reasonable amounts - like with bacon.

The absolute monster-sized gorilla in the room is sugar. Why? It works parallel to your daily intake and, if you exceed your daily sugar limit, any extra sugar turns to far* regardless of calorie intake*. This is the real issue: over 30-40 grams of sugar per day, your liver has no more capacity for sugar so it has to do something with it - it stores that as fat.

I say again: this happens independently of other food intake.

How much is 30-40 grams of sugar - man, it’s in everything in huge quantities. A regular sized can of, say, Sprite will get you close to your daily limit.

Hardest thing, the industry has been very successful in not making sugar content clear on labelling. Labelling is the battlefield - this is where lobbyists spend their money.

Google something like ‘sugar is the enemy not fat’


Staying on focus of the op -

Yeah pretty much agreeing with your first two replies. That about 15 medium sized zukes. 30 grams of fiber.

It’s a little bit more than 4 tablespoons of fat.

Of course we don’t know what that “nutritionally perfect meal replacement” would actually look like since few agree on what “nutritionally perfect” would look like, but let’s make it up and call them 50% carb; 20% protein and 30% fat. The rest of it coming all from fat or 2/3 carb and 1/3 plant protein will each still stay within reasonable macronutrient ranges.

Yes one much higher in fiber and volume which has impacts but you’ve held total intake and total calories expended as constants so given that as part of the hypothetical body mass of the two twins (and let’s make them exact clones) would be the the same. Same with the 11 teaspoons of sugar spread over the day if you did that as an arm with a third clone too. Maybe different if they were all at once.

So the liver doesn’t have capacity to … do what with it? Are you talking about converting fructose and other monosaccharides to glucose? Glucose to glycogen?

A 40 gram sugar load for the body is two slices of bread. I’ve gotten the bulk of my calories every day for 40 years from carbohydrates, are you saying that most of this has been converted to fat by the liver? And then … since I can only gain weight if I pay constant attention to eating more, it’s been what? Immediately metabolised?

I too would like some cites for that.

He started a whole tread trying to support this idea, and IMO failed to make any sort of case. My obesity: Finally an answer that makes sense! - In My Humble Opinion - Straight Dope Message Board

Ah, it’s a religion. No point in engaging then.

Oops. That should have been 11 tablespoons.

naita … is there however just some small basis for the thought if we spin it as positively as possible?

500 calories of added (“free”) sugar, 125 grams, making the total added sugar at least 25% of calories (more of course if those nutrition bars have some, which they likely would)?

Maybe not any impact on total fat, but some reasonable debate that it might, especially if ingested all at once, as in a sweet beverage, and very likely some on where the fat is (more in liver and centrally located).

I know not what he claimed.

No real situation like that exists. But even as close as you can get it doesn’t mean they’re eating the same volume of food and digesting it and using it with the same efficiency and one of them might end up with a different body size over the long run. So many other details of their individual metabolisms and environments than the difference between zucchini and butter will determine how that manifests.

Like an elephant?

If we spin it as positively as possible and remove the part that’s controversial and impossible, it stops being controversial and impossible. That’s true … :wink: