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Scientist busts myths about how humans burn calories

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Re: Scientist busts myths about how humans burn calories

#541

Post by unnouinceput »

Quote: >

So that's why I became fat as a pig since I started freelancing more than 14 years ago. Because I'm no longer stressed in corporation bullshit politics and actually enjoy working with my clients. Stress free life means less energy used, means eating will get more food transformed into fat. Also probably why I didn't exceeded a certain number, I am at current weight for like a decade now, and I still eat like a pig but I don't gain weight anymore.

Seems is time to go run for politics, increase the stress in my life /s.

Re: Scientist busts myths about how humans burn calories

#542

Post by yetihehe »

scotty79 wrote: post #514
bratwurst3000 wrote: post #451

Earlier quoted context omitted.

Yes but in numbers it is way more. If I bike for an hour I burn 700-1000kcal . Thats not 15 but 50% of the dayli calorie intake… i am no expert btw. My understanding is that the problem is more that after 20 minuts of sport, at a certain heart rate, is starting to burn fat…but not body fat. More free floating fat. And it takes one hour or so to start burning bodymass. So the fuel for one hour sport is what I ate befo…

> If I bike for an hour I burn 700-1000kcal . Thats not 15 but 50% of the dayli calorie intake… That's estimated and probably impossible. 1000 kcal is 4184000 joules, divided by 3600 it gives you around 1100W Human at rest burns about 100W. Pro-cyclist can do additional 400W. There's no way you can burn energy at the rate of 1.1kW consistently for an hour unless you literally set yourself on fire. EDIT: I was wrong.…

If you are pro-athlete, I think you could, but 1kW is probably about max a human can burn for longer periods. I managed to output 500W for 5 minutes of rowing, but I'm overweight couch potato.

Re: Scientist busts myths about how humans burn calories

#543

Post by christoph »

scotty79 wrote: post #514
bratwurst3000 wrote: post #451

Earlier quoted context omitted.

Yes but in numbers it is way more. If I bike for an hour I burn 700-1000kcal . Thats not 15 but 50% of the dayli calorie intake… i am no expert btw. My understanding is that the problem is more that after 20 minuts of sport, at a certain heart rate, is starting to burn fat…but not body fat. More free floating fat. And it takes one hour or so to start burning bodymass. So the fuel for one hour sport is what I ate befo…

> If I bike for an hour I burn 700-1000kcal . Thats not 15 but 50% of the dayli calorie intake… That's estimated and probably impossible. 1000 kcal is 4184000 joules, divided by 3600 it gives you around 1100W Human at rest burns about 100W. Pro-cyclist can do additional 400W. There's no way you can burn energy at the rate of 1.1kW consistently for an hour unless you literally set yourself on fire. EDIT: I was wrong.…

I think you need to account for human inefficiency. I have to burn more than 1 joule to output 1 joule on a bike. The average efficiency of a human on a bike is somewhere around 20 to 25%.

Re: Scientist busts myths about how humans burn calories

#544

Post by toolslive »

ajuc wrote: post #442
toolslive wrote: post #418

Earlier quoted context omitted.

roughly 3/4 of your energy consumption is maintenance (fe keeping body temperature). So you walking/biking might even be irrelevant. If the outdoor temperature was low, this would probably be number 1.

Standing still in -10C/-20C is pretty uncomfortable, but walking is perfectly fine and you even get hot after a while. So I'm not sure this is true.

it's simple thermodynamics: your body needs to keep its temperature around 37C. It needs energy for this. Heat flows from high temperature (your body) to low temperature (surroundings) via the contact surface (naked skin) or via via (clothing,...) The energy that you lose via heat transfer needs to be compensated. You burn food, fat, tissue,.... (I'm not a biologist, so I can't tell you in what order this happens)

Just try to lower the heating in your house in the winter and run around in a t-shirt iso a pullover.

Re: Scientist busts myths about how humans burn calories

#545

Post by [deleted] »

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…

[deleted]

Re: Scientist busts myths about how humans burn calories

#546

Post by itsoktocry »

irthomasthomas wrote: post #481
me_me_me wrote: post #472

Earlier quoted context omitted.

I don't get it, how is that a myth or controversial. Cutting empty calories is the easiest to remove calories from daily total. Exercise further decreases the ratio of calories in calories out. Bottom line is: calories in - calories out. There are caveats there for sure, like increasing muscle mass increases idle caloric burn. Different types of food have different effect promoting or impeding metabolism.

calories in - calories out was debunked a while ago. Different types of food and diet cause different degrees of weight gain or loss. For an extreme example compare 100 calories of glucose to 100 calories of fibre, both are types of sugar. The fibre contains an extra electron that acts like a shell, and the body has to expend energy breaking that bond to make it digestible. So most fibre passes through you without af…

>The fibre contains an extra electron that acts like a shell, and the body has to expend energy breaking that bond to make it digestible.

I'm not a nutritional expert, but...this sounds like bro science. Do you have a source for this, or can someone who knows this better speak to it?

Re: Scientist busts myths about how humans burn calories

#547

Post by edanm »

xurukefi wrote: post #299

"You can’t outrun a bad diet" seems to be the party line among fitness people these days. Anecdotally speaking that's not really true for a lot of people. I run > 100km/week pretty much all year round (most of it on extremely hillly trails) and despite my bad diet consisting mainly of pancakes, white bread, nutella, pizza, fries and burgers, I am not overweight with 78kg at 190cm. Before I picked up running I was mod…

I think I agree with your general point, and specifically agree that that statement is targeted as "mainstream advice", and might not be literally true. However, one point of disagreement:

> I run > 100km/week pretty much all year round (most of it on extremely hillly trails) and despite my bad diet consisting mainly of pancakes, white bread, nutella, pizza, fries and burgers, I am not overweight with 78kg at 190cm.

That is not necessarily a "bad diet" for weight loss purposes. It's an unhealthy diet, but as long as you're not eating too much of all those foods, it won't make you gain weight. It's only bad because most people who are eating these kinds of foods will be eating too much of them (because they are much less filling for the amount of calories that they contain).

Re: Scientist busts myths about how humans burn calories

#548

Post by toolslive »

toolslive wrote: post #544
ajuc wrote: post #442

Earlier quoted context omitted.

Standing still in -10C/-20C is pretty uncomfortable, but walking is perfectly fine and you even get hot after a while. So I'm not sure this is true.

it's simple thermodynamics: your body needs to keep its temperature around 37C. It needs energy for this. Heat flows from high temperature (your body) to low temperature (surroundings) via the contact surface (naked skin) or via via (clothing,...) The energy that you lose via heat transfer needs to be compensated. You burn food, fat, tissue,.... (I'm not a biologist, so I can't tell you in what order this happens) Ju…

If you don't believe it, just look up what the diet on a polar expedition looks like.

Re: Scientist busts myths about how humans burn calories

#549

Post by hervature »

scotty79 wrote: post #514
bratwurst3000 wrote: post #451

Earlier quoted context omitted.

Yes but in numbers it is way more. If I bike for an hour I burn 700-1000kcal . Thats not 15 but 50% of the dayli calorie intake… i am no expert btw. My understanding is that the problem is more that after 20 minuts of sport, at a certain heart rate, is starting to burn fat…but not body fat. More free floating fat. And it takes one hour or so to start burning bodymass. So the fuel for one hour sport is what I ate befo…

> If I bike for an hour I burn 700-1000kcal . Thats not 15 but 50% of the dayli calorie intake… That's estimated and probably impossible. 1000 kcal is 4184000 joules, divided by 3600 it gives you around 1100W Human at rest burns about 100W. Pro-cyclist can do additional 400W. There's no way you can burn energy at the rate of 1.1kW consistently for an hour unless you literally set yourself on fire. EDIT: I was wrong.…

You are forgetting about the efficiency of the human body. Roughly, only 21% of your power is transferred to the bike. So a professional adding 400W to the bike is actually consuming ~1900W of power. This all matches up with their nutrition [1]. Namely

> They averaged 91 g of carbs every hour across all of the stages.

That's nearly 400 calories worth of sugar simply while riding the bike. In fact, I would say cycling is a clear counterproof of this article. Their equations are literally (calories in)*efficiency = power and they know exactly how much to feed. I don't disagree that 99% of people are better served eating less, but doing cardio for 2 hours a day + diet management will lead to very quick weight loss. "Very quick" here is 2lbs/week but people have some insane expectations.

[1] - https://www.welovecycling.com/wide/2021/07/01/how-much-do-th...

Re: Scientist busts myths about how humans burn calories

#550

Post by Bishonen88 »

throwaway09223 wrote: post #206
nradov wrote: post #183

Earlier quoted context omitted.

Most people can't manage to burn 1000 kcal in a 60 minute workout. I am a large man in fairly good shape and have to put in a pretty hard effort to hit those numbers. People who are smaller or not well trained are going to be significantly lower. Measuring stationary bike workouts in terms of mph is kind of meaningless. What actually matters is the measured power output based on the resistance setting.

I'm a 40 year old guy who's been sitting behind a desk writing software for two decades. I was in good shape in my 20s but haven't exercised significantly in a very long time. It took me about three months to get up to that speed, cycling every other day. I started out doing 10 miles, at 10mph. Three months isn't all that long for an exercise program.

Not that it matters, but reporting mph for a stationary bike (indoor trainer I assume) is meaningless in this context. This could mean that you're cycling anywhere between 0 and 2000 Watts.

I cycle on and off for ~8 years (35yo) and going at 20mph in the real world for an hour or more became possible only after a few years for me.

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