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

161–170 of 753 posts

Re: Scientist busts myths about how humans burn calories

#161

Post by makeitdouble »

1123581321 wrote: post #100
josefrichter wrote: post #21

It’s sad that majority of people hit the gym or go for a run when they want to lose weight. Without diet it’s pointless. But what’s worse, diet change is also about finding a new balance that fits your body. If you start exercising at the same time, you are throwing your body drastically off current balance and it’s probably much harder to find a new one.

I wouldn't necessarily advise someone to diet without starting exercise. Exercise encourages healthier eating in a few physical ways, and for many the two are part of a mental lifestyle self-image which admittedly shouldn't exist but can still motivate. I'm also skeptical of that balance theory. A exercised body would produce more reliable eating and satiation signals to aid in balance, if 'balance' is even how the n…

The twist is that if you get healthier by changing your eating habits, it will probably be easier for to start/increase exercise, and will continue to make you healthier while you take on exercising.

Better eating is I think the most impacting thing you can do, exercising being the close second.

Re: Scientist busts myths about how humans burn calories

#162

Post by thisisonthetest »

makeitdouble wrote: post #151
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…

> losing weight happens by eating less To note, when they refer to "diet" it's probably not about "eating less" or popular "on a diet" interpretation. Good and bad diets also aren't as simple as the "CICO" myth

CICO is almost as pernicious and ubiquitous. It really grinds my gears when people try to use “intuition” to understand something super complex with no data at all. People talk about “metabolism” the same way.

Say the word “toxins” around me and I will fight you in the streets.

Re: Scientist busts myths about how humans burn calories

#163

Post by russdill »

awb wrote: post #108
mannykannot wrote: post #29

Earlier quoted context omitted.

This is purely anecdotal, with a sample size of one even if it is right, but it seems to me, personally, that exercise suppresses my appetite to some extent. I can't say that this is even real, but if it is, my best guess as to why this might be is that the exercise subtly stimulates/irritates my gut such that I am de-motivated to eat, either by feeling full or subliminally 'sick to my stomach'. After running a marat…

> exercise suppresses my appetite to some extent This is my experience as well. I also had a trainer confirm this. I used to eat before and after a workout because I bought into the idea of the body needing fuel to power the workout and fuel to recover. I ended up eating when I wasn’t hungry and feeling heavy or sluggish. She said the appetite suppression after a workout could last 30-120min and to only eat when I fe…

I feel like from reading through this thread is that everyone has a body that manages hunger and metabolism differently.

Re: Scientist busts myths about how humans burn calories

#164

Post by hombre_fatal »

esyir wrote: post #51
pverghese wrote: post #38

Earlier quoted context omitted.

Not sure what was your starting weight. But 5 kg is within the realm of normal weight fluctuations over a week for an average American.

Are you sure, I get a one or two kg swing, but 5kg of weight seems a bit extreme. I'm not American, but in my part of the world people tend to have gradual trends to weight, not sudden swings.

Weigh yourself with a digestive tract full of food and water, then weigh yourself after fasting for a day. At 200lbs I can swing the scale 15lbs/6+kg. Fat people can probably swing some serious numbers.

Re: Scientist busts myths about how humans burn calories

#165

Post by zenlf »

This is interesting. However I would love to learn more about the “doubly labeled water method”. For example, how accurate is the test result? What’s the individual variance? Do animals and humans react the same way to it?

It’s important because all the findings seem to be based on it, but the specifics are not discussed.

Re: Scientist busts myths about how humans burn calories

#166

Post by nradov »

timr wrote: post #137
nu11ptr wrote: post #93

Earlier quoted context omitted.

If you fall into a routine CICO isn't that difficult in practice. First, while sleep/stress definitely impact the equation unless you are at an unusual life crisis, the ups and downs mostly balance out over time. Second, I don't recommend counting calories, at least not in the traditional way. Instead, eat a fairly standardized diet at least on a weekly basis, so roughly the same meals (doesn't have to be exact). Eat…

I have also done almost exactly this process, and it worked for years to regulate my weight. But then I hit a plateau (a high plateau, not a low one) where I was unable to drop weight no matter how low I cut my calories. I started at a range that I knew had worked in the past, and lowered it over the course of weeks, well past the point where I was miserable. I even tried more complicated things, like varying my inta…

The most likely possibility is that you were simply underestimating your calorie consumption. A lot of people forget to count the creamer in their coffee, the candies from the office break room, the little tastes while cooking dinner. Unless you have a severe metabolic disorder your body will only burn lean muscle mass as a last resort when you have exhausted glycogen stores and can't sustain the energy demand from fat alone. Some weight training is always a good idea, though.

Re: Scientist busts myths about how humans burn calories

#167

Post by MichaelBurge »

EGreg wrote: post #156
neltnerb wrote: post #89

Earlier quoted context omitted.

For me I lose my appetite for about a half hour, I was taught it's simply blood from your stomach being used elsewhere. After a short recovery period I'm definitely extra hungry.

Intermittent fasting can help repair a lot of things in your body, make you live longer, etc. Vegans live on average 10 year longer! The hunger you feel the first day btw is not "real" hunger, it's just your stomach growling and you being used to eat. After you ignore hunger for 3 days, your body stops wanting food. That's if you want to do a cleanse. (I've never done one though)

Is it known if the meat causes people to die sooner, or is it just that people who are vegan are correlated with people who care about their health so they do other things that cause the 10 year effect?

I feel like a non-lethal poison like a flea killer or something would cause a 10 year lifespan drop, so it would be surprising if meat were as deadly as flea killer poison.

Re: Scientist busts myths about how humans burn calories

#168

Post by dahart »

dpark wrote: post #99
dahart wrote: post #43

Earlier quoted context omitted.

That’s the part that’s at least slightly exaggerated, or giving a misleading impression. Exercise absolutely burns more than 0 calories, and I definitely was burning some. Calorie burn from exercise is straightforward to approximately measure, and many people walking around with iWatches and FitBits and heart monitors are doing so. What’s well known to many people is that exercise burns far fewer calories than you wi…

I would really like to see raw data because it feels like the story being told can’t possibly be complete. This in particular feels really hand wavy: “After weeks of training, they barely burned more energy per day when they were running 40 kilometers per week than before they started to train.” What does “barely” mean? 40km/week isn’t that much in terms of calorie burn. The 100 calories/mile rule of thumb says this…

It does seem like the article is exaggerating. ;) This could be more about the author presenting a narrative than Pontzer’s data. Bringing in the sports physiologist to argue for the idea of exercise without countering the caloric claims adds a little perhaps predictable dramatic flair.

At some point, there’s just physics. Running a mile isn’t free, benching 100kg isn’t free. These things take work and we can calculate the minimum energy requirement that adaptation can’t escape. Our bodies do not adapt so far that exercise becomes pointless, it only shifts the balance a little (which might be enough to be demotivating for some people, but it’s still relatively minor.) I was under the impression that the total range of metabolic adaptivity for a given person might be on the order of 25%-30% maybe. That might be an over-estimate. I googled a little and found this paper mentioning adaptations of like 8%-15% for severe calorie restriction diets (depending on how RMR is measured).

https://academic.oup.com/fampra/article/16/2/196/480196

Re: Scientist busts myths about how humans burn calories

#169

Post by bluSCALE4 »

EGreg wrote: post #156
neltnerb wrote: post #89

Earlier quoted context omitted.

For me I lose my appetite for about a half hour, I was taught it's simply blood from your stomach being used elsewhere. After a short recovery period I'm definitely extra hungry.

Intermittent fasting can help repair a lot of things in your body, make you live longer, etc. Vegans live on average 10 year longer! The hunger you feel the first day btw is not "real" hunger, it's just your stomach growling and you being used to eat. After you ignore hunger for 3 days, your body stops wanting food. That's if you want to do a cleanse. (I've never done one though)

I hear this is a very dangerous game if taken to an extreme. You have to be very disciplined once you take it beyond 3 days. David Blaine did it for 44 days and I believe he has liver damage now? He talks about it on Joe Rogan.

Re: Scientist busts myths about how humans burn calories

#170

Post by isaiahg »

dugite-code wrote: post #25

> Exercise doesn’t help you burn more energy on average I have a problem with this hard statement based on the data because: > He realized he had to go back to basics, measuring the calories expended by humans and animals walking and running on treadmills. > He backed this up with a new analysis of data from another team’s study of sedentary women trained to run half marathons I've always heard that humans, due to ou…

What's the metric used to calculate average here? And what range of workout is included in the data. Seems like there was just too little focus given to this to call it a myth outright.

It also runs against my own experience. For the past six months I've begun exercising and changed nothing else and I've seen amazing improvement in all aspects of my life including losing fat. The type of workout I'm doing is full body and covers a range of different movements and weights. And arguably anyone serious about losing weight would do the same. If all they're doing is comparing running to dieting then I can't help but feel it's short sighted.

Post reply on HN