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Comment by paulpauper | Hacker News Reader

metabolism is orthogonal . It's possible to have a fast metabolism and still be obese if you're eating at a surplus. But it's also possible people with faster metabolisms may be more successful at weight loss if already obese. So a 300-lbs person who eats 10,000 calories/day to be weight stable will find it easier to lose weight compared to to a 300 lbs person who is stable at 4,000 cal/day. This can also explain how some people lose tons of weight on GLP-1 drugs, whereas others lose less. The guy eating 10,000 calories/day will lose much more weight more rapidly owning to having a much bigger metabolic furnace, as soon as he restricts eating and his body is no longer getting 10,000 calories/day. Unfortunately, there are no studies that investigate the link, if any, with metabolism and dieting success.

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10k calories a day is what a black bear eats preparing for hibernation. And it is what Michael Phelps would eat daily when training in the pool for hours on end.

Obese people can remain obese eating 1000 calories a day. I recall one episode of My 600lb Life and the show's featured person that day was at 900 or 1200 calories a day and still didn't lose weight. Might have still been gaining.

It is a dynamic system. People tend to only consider the CI in CI/CO.

>Obese people can remain obese eating 1000 calories a day. I recall one episode of My 600lb Life and the show's featured person that day was at 900 or 1200 calories a day and still didn't lose weight. Might have still been gaining.

How is that possible? There is a lower bound on calories needed (on average across say six months) to maintain life. Adding to that the calories needed to maintain the weight, I don't see how an obese person could stay alive with "CO" significantly lower than 1200 kcal.

And yet it happens. A doctor in my family told the story of a patient they were treating in hospital who medically needed to lose weight, and who they found unable to get any reduction until they dropped below _200_ calories a day.

Metabolism is _significantly_ more complex than CI/CO, from experience.

For how long? Irregularities can persist for a small amount of time, no doubt; but for how long does one maintain weight and life on 300 calories a day?

Come on, this is ridiculous.

CI/CO is a thing.

https://en.m.wikipedia.org/wiki/Thermodynamics

Agreeing and I found it interesting to learn more about caloric availability to the body.

I.e. calories on the label vs what the body can actually access.

Like drinking smoothies (high availability) vs raw fruit (lower availability)

Dr. Greger (Nutrition focused) discusses some of this on calorie density and some referenced studies here if interested:

https://nutritionfacts.org/blog/how-to-lose-weight-eating-mo...

I don't believe that people can gain weight while eating almost nothing, but I believe that their internal distribution of energy may be out of whack.

Proponents of naive thermodynamics model tend to assume that only "excessive" energy is stored into bodily fat, once all the other tissues have had their fair share.

That is not really true in insulin resistant people, whose storage may be excessive and leave the rest of the body unsatisfied and hungry, which drives them to eat more than a healthy person would.

To us, this looks like deliberate overeating, to them, it is a result of constant hunger caused by the fact that some part of the energy consumed is being immediately locked away in fat tissues by dysregulated metabolic processes.

Notably, it isn't easy to "correct" this situation by just eating less, because that will leave those people feeling really starved. Insulin sensitivity must be restored first, then the fat stores will give up their excess willingly and that person won't suffer.

You cant cheat thermodynamics, so something does not add up. Most likely the calorie estimates if they were self reported.

To illustrate a single 37.5g snickers is slightly below 200kcal. I probably get that number of calories just from the milk in my coffee in an average day.

Whole milk (3.25% fat) is ~60kcals per 100grams. Are you really drinking 300+grams of whole milk in your coffee per day?

What is more likely:

- a physics-breaking thermodynamic anomaly

- a food addicted person is lying about their consumption

200 kcal a day.. yeah sure. A human body needs more than that just to breathe and pump blood. Even comatose a skinny person needs 5 times as much.

Overweight people have a significantly higher metabolic base rate. Just breathing can easily be 1000kcal a day if your lungs have to move 30 kilos of upper body fat 10 times a minute. They also have more muscle mass compared to the average person their size, even when not physically active, which increases MBR as well.

Weight loss and gain is a solved problem, but self control and human behavior is not.

Perpetuating myths of impossible weight loss is not beneficial for our society and moves us further away from solving the underlying issues.

It's insane how arrogant people can be about this. You have not accounted for all of the variables and that is blatantly obvious. The phenomenon is well known and there are multi-variable equations for it, many different models. One popular model is that NEET can decrease below the caloric deficit, meaning you still gain weight by becoming subconsciously lazier despite everything feeling equally difficult subjectively. There are several other more advanced models adding other variables, some depending on insulin sensitivity, for example. Anyway, no physics is broken, laymen are just naive to the complexity abd adaptability of biology.

200kcal/day is less than 10W. Since all energy the body uses is released as heat this puts the maximum sustainable heat radiation with such a diet at 10W.

That's about the level of a typical household LED, which at most feels slightly warm to the touch.

At that energy level you could not sustain weight while maintaining body temperature let alone having a healthy metabolism. That's just a plain fact.

You will lose weight long before you reach 200kcal/day.

That's a good argument against what I said for this particular case. I didn't realize 200kcal was so little. Imagine my comment was written in reply to a higher number though because that criticism is definitely valid for a large number of posts people make in general. ;)

But it is basic physics, which is in fact being violated. It's really very normal to require exceptional proof for this. Like literally any scientific study, not just an anecdote claiming magic.

Basic physics says CI/CO applies to a closed system. Show me a closed system human and then it will be applicable.

E=MC^2 is basic physics too. So eat a pea and have enough calories for the rest of your life and then some?

You are implying that humans receive energy from another source, which is an extraordinary claim that you should motivate somehow.

Nutritional science is pseudo science at best. I had rather continue to believe in thermodynamics lmao

It is the amazing the hoops people will jump through and the lies they will tell themselves and others rather than facing the obvious truth that they are consuming too many calories.

If you treat humans as biological machines, signaling system (hormones, endocrine system) is very important. When signaling system is messed up, your CI/CO model with self-control doesn't work at all. Signals need to be fixed.

So? That doesn't disprove the premise of CI/CO. CI/CO is the notion that humans exist in the physical world and thus obey the laws of thermodynamics.

CI + self-control or will --> CO (that's the hypothesis sold by many)

CI + hormones --> CO (that's an alternative hypothesis)

> Weight loss and gain is a solved problem, but self control and human behavior is not.

Semaglutide and tirzepatide address the self control and human behavior problems. They stop you from wanting to eat more.

I can believe this as a human who fasts. I just don't eat every other day. I've fasted for multiple days. You would amazed at how much the scale doesn't move. I can lose zero weight after 36 hours of nothing but water entering me. The body is less CICO and more a system trying to maintain homeostasis as much as possible and pulling ever lever it can.

Yes, eventually eating every other day I did lose weight, but we're talking a steady glide of 1-2lbs a week nothing as severe as people would expect a severely overweight person who only ate half the week to lose.

https://www.diabetes.co.uk/blog/2018/02/story-angus-barbieri...

1000 calories is already an unbelievable claim, absolutely no one is going to believe 200. That’s just absurd

> "How is that possible?"

Eat 1200 Calories per day, drink 5Kg of water, water retention, body mass and scale weight goes up with increasing water weight?

It happens because we act like calories are calories when it's clearly not true.

Calorie counts in nutrition data are generated by something like burning the food in a bomb calorimeter. Which is most definitely not what our bodies do. We have all kinds of different biochemical ways of metabolizing different types of foods.

So someone eating 1000 calories of day could be eating very healthy or they could be ingesting a whole bunch of garbage full of sweeteners. It doesn't seem like anyone really understands how it works but all those sweeteners are more likely to make you gain weight.

Why is it that people claim the laws of thermodynamics do not apply to humans?

Because our metabolisation mechanisms are extremely complex and many things, like genetics, decide how we metabolise food; we are not petrol engines.

Obviously the laws of thermodynamics apply, but the most naive application of the laws of thermodynamics doesn't.

A human body isn't a bomb calorimeter and it doesn't perfectly combust everything you eat.

No one is claiming that the laws of thermodynamics do not apply to humans.

I'm sure an obese person claiming to eat 1000kcal per day can still gain weight but that is largely due to selfreported calorie estimates being a bad measure. Put that person in a chamber where calorie intake is controlled and I'd bet the effect disappears.

Ate only 1000kcal in food. Added in 1400kcal in sugary drinks and 2000kcal in small bites of this and that (that don't need to be counted, because it's just one spoonful of peanut butter!)

The small bites have doomed me in the past until I charted and realized the impact.

Yeah, I don't know if it was that episode or from somewhere else, but there was a similar thing where they followed the person around for a day and it turned out they didn't count anything ate as a snack between meals. They were accurately counting their meals, but including the snacks went somewhere above 3000 a day.

Secret eaters, a British show.

As somebody who went through successful weight cuts at least 3 times I must notice that not losing weight on 200 calories a day is... a very unrealistic situation. Even a 1000 calories is starving.

(I do weightlifting, and controlling one's weight is basics of everything in the gym)

This is completely and obviously untrue.

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