Why exercise isn't much help if you are trying to lose weight | Hacker News Reader

Why exercise isn't much help if you are trying to lose weight

newscientist.com

34 pointsstevenwoo47 comments

Everyone seems interested only in weight loss. But the scale is just a poor proxy for what people actually care about ( looks, health or physical aptitude ). Your bodyweight remaining the same while gaining muscle should also be a huge win since that's building muscle, bone density and losing fat.

Do people actually just want to lose weight momentarily through diet? Instead of keeping it off long term, which is way easier achievable through diet + exercise?

Also no mention of body composition, bone density and cardiovascular health, which should be the actual metrics, instead of the proxy used for them.

I'm interested in weight loss because my BMI is over 30 which is considered obese regardless of whether it's muscle or not. I should not have a third of this weight. A couple years ago, I bought an electric scooter and it could not carry me because of the weight, so I ended up having to return it. Nowdays I have one that costs four times more and can carry me, but I still weigh much more than I should!

this is true for weight loss while in a mostly health range. it isn't true for people with high BMIs. for them the scale is a mostly direct match to health and how they look

I think they are also at risk from the BMI simplification and the goal as presented in the article. The wrong crash diet approach can be raising their % body fat while lowering their BMI. If they weren't weight lifters that's probably putting them in a high risk group that isn't usually identified in studies.

human bodies are incredibly optimized to store energy for bad times and maintain a good balance at the ideal level. this is why the whole "calories in calories out" is technically true but mostly useless for a lot of people as the calories out is a very hard to compute variable. it also ignores entirely the negative effects of muscle loss.

there is a lot of complexity and difficulty in long term weight loss, we are fighting biology hard there. that's why glp1 agonists are having such a success, they allow to fight hormonal homeostasis with proper weapons.

I have yet to see any research showing a way to durably affect the body's set balance, which would be the revolution.

but this research all in all confirms what we know: * high intensity muscle fiber tearing exercise is much better at not affecting metabolic compensating mechanisms * cardio might be good for health and other things, it's very much neutral or possibly negative for weight loss, as cardio does not build muscle mass * pure diet changes are difficult to make sustainable for many. I have seen it first hand where a constant 300 calories deficit a day resulted in weight gain and muscle mass loss despite cardio.

calories in calories out isn’t true at all

as a simple example consider eating 100 calories of vegetables vs 100 calories of pure sugar. your body has to work a lot harder to digest one of those vs the other

A more importantly you’ll still lose weight if you eat 1200 calories of sugar daily if you’re burning 1500 daily.

and you’ll lose even more if those calories are not ultra refined carbs

Sure, but at this point we’re interested in helping people lose weight who just “can’t”.

Fix the major health problem, then refine the details.

Humans are no different than other mammals.

Look at overweight house cats and dogs. How did they get overweight? How do they lose weight?

Calories in / Calories out is the definition of survival or not for wild mammals.

Calories out is also exceedingly easy to calculate- on any given week if you gain weight the out is less than the in. If you maintain its ahout equal. If you lose weight out is higher than in.

Nothing else matters.

Diet is king but exercise is not to be underestimated in its contribution.

I have found major success with fasted cardio. That is to say, timing when the exercise occurs relative to your most recent meal seems to dramatically modulate the effects.

If I do an hour of cardio within 12 hours of eating, it feels "normal". Nothing to write home about. If I do the same routine but I've been fasting for longer than 12 hours, I can feel my mitochondria light on fire after about 40 minutes in. The first few times I did this I stopped because I thought I was going to die. It felt super weird to me. Like a very strong parasympathetic response. You do get used to it though. I think this is one thing that can actually affect certain fixed points in your metabolism. If you go from zero to 80% VO2 max and keep it there for an hour on an empty stomach, that energy has to come from somewhere. And it has to happen pretty damn quickly. I think the time pressure for energy delivery under adverse conditions is what makes this so impactful.

> I can feel my mitochondria light on fire

What is this supposed to mean?

BroScience.

What point are you even trying to make? The energy comes from your glycogen reserves and then from fat, both in a fasted vs non-fasted state. And if calories are equated at the end of the day, you just made your workout way harder because you didn't fuel properly.

> you just made your workout way harder because you didn't fuel properly.

Not necessarily. I feel way better when I work out in the morning without any food first. I think it's because my body doesn't have to spend any energy digesting food while exercising. This is true whether I'm doing a weightlifting session or a few hour trail run

It is because this subject is the closest to modern voodoo of all modern activities.

I rolled the bones myself and it seemed like it worked, therefor X.

No, I rolled the bones myself and it seemed like it worked, therefor Y.

We would first have to define what we are even talking about by "energy" and "workout" to have any kind of real conversation.

The popular mind on this subject is also not even up to the point we sequenced the genome. What people think of as truth is mostly repeating things from the 1990s.I rolled the bones myself and it seemed like it worked.

Well I think it largely depends on how well trained you are because metabolic flexibility is something that gets trained. Without it your body has a hard time burning fats for fuel and so you'll feel terrible if you don't have an immediate glycogen store. When you are well trained you can do things like literally run several marathons while fasted which is documented. So whether it "works" or not will just depend largely on if your body has adapted to it

This is just my own observations, but I find that when cutting calories I need to really optimize the rest of my life to avoid crashing in energy. Sleeping well, no alcohol, plenty of caffeine, lots of water and electrolytes, and time my carb intake. Doing a simple deficient will usually either not work, or lead to my energy completely crashing.

By how much are you cutting calories? At first glance it seems somewhat excessive if it affects your life so much. Also do you live in a very hot area or do a lot of cardio? Otherwise thinking about electrolytes is way too overrated

I like to experiment with a variety of diets / deficits. On some of the more extreme ones like week long water fasting, or Lyle McDonald's rapid fat loss diet, you absolutely need to consume electrolytes because you're not going to get enough passively through eating. Personally I don't have a lot of success with very mild 200-400 calorie deficits, where electrolytes are not a major concern. I suspect it's due to factors related to the linked article, and that in general, the margin for error is much smaller.

It's probably because the calorie maintenance is a range and not a set number so you have to adjust accordingly so if you eat less -> you move less -> tdee goes down. All those while you feel lower energy and hungrier. That's where exercise comes in as a satiety regulator.

If 200-400 kcals deficit doesn't work, just lower by 100 more each week until you get to a desired weight loss rate.

I've found great success with this approach and also changing my thinking to 'is this thing something sustainable and healthy long term?'. Like of course I can lose a lot of weight fast with a huge deficit, but then I'll just default to my initial habits and gain it back.

I also find that exercise has an influence on my cravings and on what I eat generally. It basically makes it much easier to avoid stuffing my face with random calorie laden foods.

I agree that it's a range, and that's precisely why it's hard to get right. If I go for a day trip on the weekend with my wife I might burn 1000 extra calories walking. If I have a mystery coffee at my friend's house I have no idea how much I just consumed. The margins are too close that it becomes difficult to make consistent progress.

Sure it can be difficult, especially if you compare day to day, but if you compare or weekly bi-weekly averages ( both weight and calories ) it becomes way more doable. Are you just supposed not to try since you can't exactly find the numbers each day?

With the approach above you don't really care about acute changes in intake or activity and look at the bigger picture and change the things that are constant and under your control.

It's not simple but it also doesn't mean you should just give up.

Yeah, but why do something difficult when you could do something easy? Going on a 300 cal deficit a day, you have 2100 calories a week. A couple bad days could easily throw off all your progress, and you might not even know what messed you up. If I eat at a 3000 cal deficit I'm gonna lose weight even if I don't do things perfectly. Go out for ice cream? Skip the gym? Who cares?

Egh pontzer and his misinterpreted studies again.

Exercise burns extra calories, just not as much as one would expect based on simple calcs.

At least this time the article is mostly okay, last article I saw here a while back was basically saying exercise doesn’t burn extra calories despite his works actually showing levels of activity influencing ~1,000 calorie difference in energy expenditure. Although speaking from experience, good luck trying to maintain high activity levels if one underfuels.

You can run a marathon a month or not drink a coke a day or eat one less slice of bread. Exercise is important for your health but it’s not how one loses weight.

This ignores metabolism. If you are in a state of high caloric excess (i.e. you eat more than you need every day, like most modern humans) and then you reduce your calories a bit, you'll see some initial minor weight lots, but then your metabolism will simply compensate.

To see real weight loss over a period of months you need to push past the point of metabolic adaption and stay there. Dropping a slice of bread won't cut it. That's why weight loss is so hard.

That's why exercise is useful for weight loss even though it won't do much by itself. You'll need to use every tool at your disposal to burn those excess calories.

    dropping a slice of bread won't cut it

But it will cut it, assuming you're moving your body the same amount every day. It just may take a while if you only cut a single slice of bread and you're wanting to lose a lot of pounds.

Your body mass doesn't materialize out of nothing. Food in, body mass out. Less food in, less body mass out. Simple as that. Everything else is optimization that's not really required, just eating less, patience and consistency.

His point was when you eat more calories than you need, then the body can afford to be sloppy (inefficient) about absorbing all those calories.

When you cut down a little on food but are still above or at your daily calorie requirement, the body can adapt by increasing its conversion absorption efficiency and in that case one wouldn't lose weight, because metabolically it's still absorbing the same amount of calories.

Interesting thought.

Do you have a source I can read through to understand more? I couldn't find anything supporting that idea.

Before dieting, I would expect most people to be in energy equilibrium, where their weight matches their calorie intake and calorie expenditure. Changing one side of that equation will change the equilibrium, every thing else equal.

If you eat more, you will gain weight. If you eat less... you will lose it. If you want to keep losing it, you have to keep eating less. Every target weight has an associated calorie intake / expenditure.

No doubt there are metabolic levers to pull to optimize the timeframe and that psychology and lifestyle play a big part of caloric intake, but, again, thinking about all that isn't really necessary.

Just eat less that you used to and be consistent about it. And if you're feeling spry, move more than you use to too. Keep tapering down until you're at your goal weight. This is the diet that is probably the best fit for 99% of people who are overweight. Dumb simple. No way to fail. Literally nothing to think about except the spoon, and maybe which route you're going to take walking around the block.

https://pmc.ncbi.nlm.nih.gov/articles/PMC4803033/

https://www.researchgate.net/figure/The-Constrained-Total-En...

https://en.wikipedia.org/wiki/Exercise_paradox

Those are mostly just arguing that exercise isn't a good way to lose weight. No disagreement about that, although to be super nitpicky, "not good" doesn't mean "doesn't work", they just suggest that there is a cap on how much exercise you can do before your body stops burning more calories, so there's an effective limit on that side of the energy equation.

Also, from the second one:

    Long-term maintenance of weight loss requires sustained energy balance at the reduced body weight. This could be attained by coupling low total daily energy intake (TDEI) with low total daily energy expenditure (TDEE; low energy flux), or by pairing high TDEI with high TDEE (high energy flux

That's exactly what I'm arguing above.

A marathon a month is less than a mile a day. Semi regular exercise is an excellent way to burn some extra calories. Especially when your weight is relatively stable and your diet isn’t completely awful (so it’s not trivial to make huge improvements for little effort).

This isn’t even getting into the many benefits of exercise in general, or the virtuous circle of "well I didn’t particularly enjoy that hour on a bike in shitty weather so I refuse to waste the benefit on a shitty donut purely out of spite".

Sure but run a mile a day or eat one less slice of bread is an easy choice for most people looking to lose weight.

No mention of cardiovascular health?

"Exercise" in these studies could be something like leisure walking for a couple of hours. That can only affect your weight by keeping you away from your snacks for a couple of hours, its energy expenditure is not moving your weight in any direction. If you look up, the energy cost of light activity is exaggerated. You can get numbers as high as 1 kcal / (kg*km) so somebody who is 100kg (220lbs) supposedly burns 500 kcals in a 1 hour of walking at 5 km/h (20 minutes mile). I know people who believe these numbers, think themselves at a caloric deficit and, when still gaining weight, doubt the Thermodynamics instead of the exercise "science".

I like the approach of some bodybuilders when trying to lose weight. They just count the cardio as extra, and multiplying the calories burnt by 0 to 0.5 when cutting.

Losing weight also becomes quite straight forward when one tracks their calories and activity in minutes and uses weekly averages. That way changing one side while maintaining the other can get them to losing weight again.

I agree totally with you, people try to find the perfect equation and tracking method for everything, otherwise it's pointless to them. Honestly I like how it is like a game, where losing weight initially is simple and then it gets incrementally harder and you have to find better methods and how there's variations from person to person.

One can actually measure the work done in cardio - chest HRM or pod can measure running through acceleration, and bikes and rowing machines can have power meters, measuring work applied to the drive axle. It's not the consumed energy but the aerobic COP does not change much so it's easy to estimate the consumed energy from the work done. Because the power output during an activity can vary by orders of magnitude, the time in activity is a very poor estimate IMHO.

TLDR - your body compensates by using less energy in all other activities if you do aerobic exercise, more so if you cut back on calories in. This appears not to happen with weightlifting. They directly measured energy burned with doubly labeled water.

Is it more difficult to lose than to gain?

It sucks that losing weight is just impossible unless you change every habit you have instantly and totally and sustain that for the rest of your life. Otherwise your body will balance out anything you ever try to do in a way that makes it totally ineffective.

One could just start slowly with something like learning to make delicious food that's not as calorie dense or going for an activity like rock climbing or basketball with friends once a week instead of going to a restaurant.

Yes, you have to sustain them for long periods of time, but that doesn't mean they can't be fun.

There's so much friction just getting to the point of even trying any one of those things that it just feels unattainable. Because you have to make it your whole life if you want to have any hope.

What's the alternative then? Just succumb to your habits? And maybe life is decent now, but it only goes downhill and gets more difficult physically as we age. Do you really want the you in 10 years to hate the you now?

I like Yvon Chouinard's approach when choosing sports too, he'd chose one that's fun, do it while enjoying it and once it feels like grinding he'd just move on to another sport that's fun again.

I understand that it's difficult, but it's something that affects all other areas of your life, so you shouldn't just give up.

I mean, I have dissociative identities, so I don't even have to hate the me of 10 years ago -- parts of me already hate other parts of me in the present, with a passion... but, I digress.

> I understand that it's difficult, but it's something that affects all other areas of your life, so you shouldn't just give up.

Yes, of course; I have some major executive dysfunction in pretty much all areas of my life, so this checks out... I don't "just give up" per se, I just don't know what to do, and then the habits keep happening in the background. I'm mostly autopilot these days, due to the constant overwhelm (even though I don't like it).

For me its hard to just eat healthy, I need to also be working out to get into the "groove". Like I'm less inclined to eat something I shouldn't if I've worked out.

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