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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

#561

Post by mantas »

itsoktocry wrote: post #546
irthomasthomas wrote: post #481

Earlier quoted context omitted.

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?

Not sure about exact process. But whole fruit has dramatically lower glycemic index than juice of the same fruit.

Re: Scientist busts myths about how humans burn calories

#562

Post by jimmyvalmer »

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…

Verbiage is proof of work, and journalists need to make a living, just the same as planning-to-plan product managers.

You can train yourself to skim for maximal extraction per minute. I burned through the article in about 3-4 minutes. I tend to get bogged down by my software developer's close-reading instincts.

Re: Scientist busts myths about how humans burn calories

#563

Post by nradov »

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.

Color me skeptical. In order to burn 1000 kcal in 60 minutes a cyclist would have to sustain a power output of about 280 W. Do you have a calibrated power meter, or are you going by the "vanity" calories displayed by most stationary bikes?

There are certainly plenty of trained cyclists who can maintain that power output, but I've never seen anyone reach that level after only 3 months. If you really did that then you're an extreme genetic outlier with an unusually fast training response.

Re: Scientist busts myths about how humans burn calories

#564

Post by wtetzner »

edanm wrote: post #535
irthomasthomas wrote: post #481

Earlier quoted context omitted.

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…

> calories in - calories out was debunked a while ago. No, it wasn't. It's the generally accepted model of human weight gain. It's what most scientists who study this topic believe to be true. (And really, it's the only model that makes any sense, and is incredibly easy to test) They only people who disagree with this model are considered to be outside the mainstream of science. They might be right (I don't think so…

Obviously if you eat fewer calories than you burn, you’ll lose weight. But the inverse is not necessarily true. It’s possible to consume more calories than you burn and still lose weight, because your body doesn’t necessarily utilize all calories consumed.

Re: Scientist busts myths about how humans burn calories

#565

Post by nkurz »

balfirevic wrote: post #552
KennyBlanken wrote: post #94

Earlier quoted context omitted.

A few hours on my bike can be 2,000-3,000 additional calories over base metabolic rate. That's not based on made-up calories but actual work from a power meter on the bike. "You can't exercise your way out of a bad diet" - literally not true for a fuckton of endurance-sport athletes for whom the challenge is eating enough calories. It's 100% true for people who think exercising for 30 min means license to eat whateve…

> A few hours on my bike can be 2,000-3,000 additional calories over base metabolic rate. Are you sure? 2000 kcal in 3 hours is 770 watts of power output. Edit: Wikipedia [0] says "During a bicycle race, an elite cyclist can produce close to 400 watts of mechanical power over an hour and in short bursts over double that - 1000 to 1100 watts; modern racing bicycles have greater than 95% mechanical efficiency. An adult…

You are forgetting that the human body is nowhere near 100% efficient at burning fuel to put power into a pedal. To produce 400 watts of mechanical power, the body consumes about 4 times that amount of fuel (25% efficiency). Consuming 2000 kcal over 3 hours is thus closer to the more realistic 200W of power to the pedals, and even the higher ranges make sense if he's a good athlete. See this article: https://www.welovecycling.com/wide/2020/05/14/how-to-convert...

Re: Scientist busts myths about how humans burn calories

#567

Post by uhtred »

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…

You need exercise and a healthy diet to lose weight. Sure you could sit on the couch all day and eat very little and you'd probably lose weight, but you'd have to eat so little that it probably wouldn't be possible without developing an eating disorder. However, if your diet is really bad, eating way too much sugary food, then yes, exercise alone won't really help much.

Re: Scientist busts myths about how humans burn calories

#568

Post by elevaet »

deepnotderp wrote: post #282

The conclusion is almost certainly wrong: 1. From a simple sniff test, if this were true, then athletes wouldn't need a lot of calories. This obviously isn't true, eg Phelps eats 8-11K calories a day. I personally eat around 3.5K calories a day. If exercise didn't impact caloric burn I assure you I'd be a lot fatter... 2. The only plausible mechanisms for why exercise wouldn't result in more overall caloric burn is t…

> 1. From a simple sniff test, if this were true, then athletes wouldn't need a lot of calories. This obviously isn't true, eg Phelps eats 8-11K calories a day. I personally eat around 3.5K calories a day. If exercise didn't impact caloric burn I assure you I'd be a lot fatter...

I agree and I'm in the same boat. After 10 years of running ~70km/week, I'm eating way more, have dropped 20lb, and am healthier and stronger.

> The implication of this is that somehow the sedentary lifestyle of your average couch potato is the "normal" lifestyle for a body, and the lifestyle of a hunter gatherer is "overactive", and their bodies are chronically tired and trying to reduce their metabolisms. That... seems quite unlikely.

I think people underestimate what being active and excercise actually mean. Our ancestors were vastly more active than we are today. The amount of movement that was required for foraging, hunting, agriculture is hard for most modern people to imagine.

Even the act of preparing the food that was gathered/hunted/harvested was so much more manual and energy intense than what we are accustomed to today.

For most of our evolutionary history basically everything we did was powered by our bodies. Today we have machines for everything, and a high standard of comfort.

It's true that calorie restriction is easier for most people than excercise, but I think it's because.. to put it bluntly.. we've become lazy.

Re: Scientist busts myths about how humans burn calories

#569

Post by jghn »

irthomasthomas wrote: post #521
jghn wrote: post #520

Earlier quoted context omitted.

It’s still calories in vs calories out. What changed is that our understanding of what determines calories in and calories out has become more nuanced. For instance, your examples

My examples demonstrate that calories in / calories out is false. I don't quite get your point? A calorie is a measure of the useful energy released from burning stuff in a furnace. It was invented to compare the efficiency of different fuels for steam engines. It has no relevance to humans, who don't use a furnace and steam power, but a complex chain of cascading chemical reactions.

What I mean is that "calories in" is not literally calculated by the total energy you put in your mouth, but rather the energy your body absorbs from that. And as you note that might be different based on the food, how the food is prepared, content of the food, etc.

Likewise "calories out" is not literally calculated by adding up your movement & exercise. We know that things like hormonal levels, etc can all impact how much energy your body is expending.

Re: Scientist busts myths about how humans burn calories

#570

Post by AnIdiotOnTheNet »

artdigital wrote: post #378
rob74 wrote: post #349

Earlier quoted context omitted.

Congratulations! I would be happy to lose "only" 10 kg (hell, 5 kg would be good for a start), but since Covid and home office my weight has been (slowly, but steadily) going in the wrong direction. Yeah, you can and do burn calories by exercising, but it's depressing how little it is. And it's also depressing if I look at the graph that some 40 to 50 year olds seem to still have the metabolism of a toddler - I'm def…

My advise: (as someone who does a lot of working out and calorie control) Write down what you eat for a while and its calories. Weigh yourself daily as well and write that down too. If after a week your weight went up: Your calories are above your TDEE. If it went down: Your calories are under your TDEE. And that's basically it, once you know what your TDEE is, eat under it to create a caloric deficit and you will lo…

> Write down what you eat for a while and its calories. Weigh yourself daily as well and write that down too. If after a week your weight went up: Your calories are above your TDEE. If it went down: Your calories are under your TDEE.

Not necessarily. It is important to remember that water weighs ~1lb/pt and there are a lot of things that affect how much water your body is carrying at any given moment. Depending on your body mass, it is not unrealistic to see 5lbs of fluctuation in a single day. On a calorie restricted diet your body will tend to retain water (because it does this for pretty much any stressor), so you may actually see a slight increase in body weight at first even though your TDEE is above your caloric intake.

A more reliable approach, in my opinion, is to do the TDEE calculation for your target weight and set that as your calorie limit.

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