Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Scientist busts myths about how humans burn calories

science.org

Post reply on HN
Print view View original

311–320 of 753 posts

Re: Scientist busts myths about how humans burn calories

#311

Post by lordnacho »

zmmmmm wrote: post #296
lordnacho wrote: post #261

Earlier quoted context omitted.

But you can eat the calories you spend in just a few minutes. If you have a pile of Mars bars, that will supply enough energy to compensate an hour on the treadmill. Might not be the typical thing an athlete eats, but it certainly keeps the weight on a lot of people.

But that goes to the other part of the fallacy, because even if you eat a pile of 10 Mars bars, a large amount of that will just get excreted. Meanwhile you'll start to feel physically sick and probably your body will then reject food for a while. CICO does more harm than good in IMHO because you're talking about a complex system.

IMO CICO is right but not useful. It's like saying that if you just read math books and did the exercises, you'd get a math degree easily.

That's true of course, but the problem for most people is sticking to the plan, not whether that plan would actually work.

We see athletes sticking to their plans but they are pretty special in terms of what they can get themselves to do.

Re: Scientist busts myths about how humans burn calories

#312

Post by rdiddly »

Last thing I saw was "The son of two high school English teachers, Pontzer grew up on 40 hectares of woods in the Appalachian bla bla bla..."

You know that sentence. So many articles have that sentence. The one where it veers off course to talk about the (usually uninteresting) person who found the thing the article is ostensibly and nominally about. Am I alone in being perfectly happy reading about science for the duration of an article, and not particularly caring about the scientist and what breed of dog he has etc.?

Re: Scientist busts myths about how humans burn calories

#313

Post by zmmmmm »

SergeAx wrote: post #257
urthor wrote: post #114

The thing is, exercise still reduces appetite. It raises the blood sugar levels as the body supplies the muscles with carbohydrates, and triggers a complementary response in appetite hormones. Finally, and most importantly: Exercise releases dopamine. Dieting is universally a mood killer, because kilo-joule deficit equals starvation. So whilst it does not directly impact weight loss. It still makes it (a bit) easier.…

> exercise still reduces appetite Please be careful generalizing anectodal facts. Lots of people, me included, have otherwise experience.

I feel like it's a more complicated story going on.

Post exercise I will often have a sort of hunger roller coaster. Naively, imagining the body's metabolism, hunger is responding to perception of a calorie deficit in the blood : organs demanding energy and blood sugar decreasing, forcing burning of calories from stored reserves.

But what if your body is able to efficiently maintain glucose levels? in that case exercise might not induce hunger, in fact it might be that exercise stimulates alternative pathways that release energy and these stay active even after you finish exercising. This might well be much more the case for well trained athletes than regular people. Or it might depend on diet or loads of other factors.

Personally, I have found that exercise is nearly pointless any time other than right before I eat. So exercising before breakfast is perfect because the stimulated hunger response is immediately satisfied by eating breakfast. But I don't eat more breakfast than I usually would, so it's a win.

Re: Scientist busts myths about how humans burn calories

#314

Post by stormbrew »

__MatrixMan__ wrote: post #308
ewindal wrote: post #281

Earlier quoted context omitted.

You’re reading that wrong. Of course you burn more calories through exercise. Michael Phelps couldn’t have eaten 12k cals a day if exercise didn’t burn calories.

Is it certain that we absorb all of the calories we consume? I went on a backpacking trip with my friends recently and despite similar activity levels everybody was surprised when they noticed that I eat twice as much as anybody else in the group. Maybe I should bring it up with a doctor, but I feel fine, I just also spend more on food than most.

Yes, this. These conversations about weight loss are so rife with spherical cows and people come to ridiculous generalizations because of it. Bodies are complicated and varied. "Michael Phelps eats 12kcal a day and yet he's not fat" is just a correlation, it doesn't mean anything. He's an extreme outlier of a person in many ways.

Re: Scientist busts myths about how humans burn calories

#315

Post by ehnto »

14 wrote: post #218

I came up with a diet to lose weight. I was approaching 200lbs and wanted to get it under control so made a simple diet that helped me lose 50lbs. I call it the half and half. You take your meal and plate it. Then take a second plate and split everything exactly down the middle. Eat your first plate and then you wait half an hour. If after half hour you want to eat again you can go back to your second plate. What end…

You might have heard of it by now but I suspect you're exploiting the mechanism that delays the feeling of satiation for roughly 20 minutes after eating. Many people can eat a seemingly unlimited amount of food so long as they do it quickly.

I think your method is cool because it tricks both the hungry and the logical part of your brain into thinking it can totally have all the food so long as it waits, but by the time 20 minutes is up, the satiation chemicals have found their way to your brain and it's no longer hungry.

Re: Scientist busts myths about how humans burn calories

#316

Post by xanaxagoras »

dahart wrote: post #4

> “You can’t exercise your way out of obesity,” […] “you can’t outrun a bad diet.” While this article is being a bit dramatic and possibly understating the impact of exercise slightly, I feel a little dumb that I didn’t know this earlier. It took me several decades too long to understand the obvious, that exercise is for building strength, and losing weight happens by eating less. I tried for way too many years to ex…

In my (extensive) experience, losing weight is predicated on accurate calorie counting. The trick is to use exercise to lighten the perceived difficulty of your caloric deficit. For example if you're trying to lose a pound a week, it's a lot easier to eat 250 cal below your TDEE and walk for 2.5 miles than it is to eat 500 cal below your TDEE.

Re: Scientist busts myths about how humans burn calories

#317

Post by csee »

dahart wrote: post #4

> “You can’t exercise your way out of obesity,” […] “you can’t outrun a bad diet.” While this article is being a bit dramatic and possibly understating the impact of exercise slightly, I feel a little dumb that I didn’t know this earlier. It took me several decades too long to understand the obvious, that exercise is for building strength, and losing weight happens by eating less. I tried for way too many years to ex…

This misses the point of the article, it isn't that you unconsciouly eat more when you exercise, it's that moderate exercise simply doesn't burn that many calories (if any) once your body is accustomed to it.

Re: Scientist busts myths about how humans burn calories

#318

Post by ajuc »

__MatrixMan__ wrote: post #308
ewindal wrote: post #281

Earlier quoted context omitted.

You’re reading that wrong. Of course you burn more calories through exercise. Michael Phelps couldn’t have eaten 12k cals a day if exercise didn’t burn calories.

Is it certain that we absorb all of the calories we consume? I went on a backpacking trip with my friends recently and despite similar activity levels everybody was surprised when they noticed that I eat twice as much as anybody else in the group. Maybe I should bring it up with a doctor, but I feel fine, I just also spend more on food than most.

I was eating similarly in my 20s and 30s and in 20s I kept about 80kg but in 30s I got to 130kg :/

BTW there are diseases that reduce calories absorbed, you might want to get checked for colitis ulcerosa and crohn's disease. They have nasty side effects so better to know earlier even if you don't have the worst symptoms.

Re: Scientist busts myths about how humans burn calories

#319

Post by joeld42 »

rdiddly wrote: post #312

Last thing I saw was "The son of two high school English teachers, Pontzer grew up on 40 hectares of woods in the Appalachian bla bla bla..." You know that sentence. So many articles have that sentence. The one where it veers off course to talk about the (usually uninteresting) person who found the thing the article is ostensibly and nominally about. Am I alone in being perfectly happy reading about science for the d…

There are different kinds of articles out there. Some are about getting the information across, some give the context and the story behind it. Some aren't even about the science at all. I wouldn't compare John McPhee to a Geology textbook. And I wouldn't say it's correct that this article was "ostensibly and nominally" about just calories. The headline is "Scientists bust myths about calories". It's about the scientists as much as it is about the calories.

Anyways, that's all to say, I do enjoy articles like this that give context and explain not just the research but the people behind it. Let people enjoy things.

Re: Scientist busts myths about how humans burn calories

#320

Post by csee »

ewindal wrote: post #281
y4mi wrote: post #266

Earlier quoted context omitted.

And yet the article you're commenting on says that you don't burn more calories by exercising... If it is true, it definitely changes the narrative.

You’re reading that wrong. Of course you burn more calories through exercise. Michael Phelps couldn’t have eaten 12k cals a day if exercise didn’t burn calories.

Well that's what the article says. The Hazda who walk 8-12 km a day burn the less calories as an average American (or the same after adjusting for body weight).

Also that Phelps thing is highly questionable. He says he "probably" burns 8-10k, not 12k. Not the type of statement you want to rely on to dismiss all this work.

Post reply on HN