Obese People Burn Calories Less Efficiently, Even After Weight Loss Surgery | Hacker News Reader

Obese People Burn Calories Less Efficiently, Even After Weight Loss Surgery

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16 pointspaulpauper28 comments

Interesting usage of the term "efficient". Looking at an organism, one would presumably say that the organism that burns fewer calories is more efficient. A more efficient car burns less fuel, for example.

But this article uses "efficient" to mean "efficient at burning more calories".

"To measure people's calorie-burning efficiency, Dr. Indelicato took resting metabolic rate (RMR)--the amount of calories a person needs to burn at rest per day in order to maintain their body weight—and divided it by weight. The result is the metabolic factor (MF), which shows how many calories a person burns per pound of their body weight. The higher the MF, the faster the metabolism."

I'm not saying it's wrong - I'm just saying that we live in a strange time when our bodies haven't evolved to cope with excess calories in our diet.

It's of course a complete inversion of how 'efficient' is used in other contexts.

Obese people are much more efficient in how they use the consumed calories and it's only our "obsession" with being slim that makes the scientists involved use such a twisted interpretation.

For almost every creature in almost every possible context, being obese is an objectively good thing. Being obese means being successful in gathering resources, being successful in avoiding unnecessary effort and struggle. Being obese is the mark of a good mate.

It's only with our usage of the game engine exploits of "cooperation" and "tool use" that we've gotten into a situation where our culture (and bodies) is completely unable to cope with the massive amount of energy we have available.

It's a strange place to find itself for any species.

>I'm not saying it's wrong

I am saying it's wrong. Efficiency has a very clear definition in science. Any paper abusing this is unscientific and should have never been published.

We have a few words that are very specific in science. We should not muddle our ability to think about problems by using unclear language.

Well, it’s not wrong. Efficiency is really just a measure of how much work it takes to achieve some result. If your unit of work is “exercise” and your end result is “burning calories”, then clearly a body which takes more exercise to burn the same number of calories is less efficient at achieving that result!

How surprising is this? Think of a thin person and a large one of the same height. Consider they're both sitting normally dressed at room temperature. The body will dissipate heat over its surface area.

Surface area is proportional to linear measure squared, volume to linear measure cubed. But given constant height, surface area varies with linear measure, and volume to linear measure squared.

So a quadrupling of volume/weight results in a doubling of surface area. Now if maintaining body temperature above room temperature is a significant expenditure of energy, it would be expected that larger people are more energy efficient and thus less 'efficient' at burning calories per unit weight.

Evolution takes time. We'll get there eventually if we don't kill ourselves off first. I'm increasingly thinking genetic engineering might not be so bad after all. Between our swiftly changing diet, lifestyle, and environment we may not have the luxury of doing things the traditional way. If we were able to do things like make sure our next generation was born with the ability to filter PFAS and microplastics from their blood they could at least drink the water on our planet without poisoning themselves.

>I'm increasingly thinking genetic engineering might not be so bad after all.

Until you genetically engineer all humans to waste calories, crops start failing due to climate change and soil depletion, and humanity dies because of this.

Efficiency might not be good now, but looking at the longer timeline, I don't think we should reasonably assume that the abundance will last. Actually with how things are going right now, I would assume abundance to end in my lifetime.

Why should our bodies evolve to become less efficient and thus to lower our survival capabilities?

I think the evolution at play here is not there. It's in self-control and being to maintain a healthy diet in the face of abundance. Indeed, those who can't do that and, for instance, become obese lower their survival rates because of the negative consequences. However this does not seem to affect reproduction rates (or does it?), which is key for evolution.

There's just no reason for any animal to evolve the necessary "self-control" to not eat available food. This situation - abundance of food - almost never comes up "in nature" and when it comes up, it's a good opportunity to stuff your face.

>> “Would you make an active decision to spend the rest of your life on 1,200 calories a day?” he asked. “If you're going to go on a diet, if you're serious about losing weight, this is the end game, and it's a different conversation.”

This is what "dieting" looks like, a lifelong commitment to restrictions.

1200 a day is severely limited, though. 2200/day is a normal amount for a normal man to get by on, more around 1600-1800 if actively trying to lose weight. You're talking about eating nearly half as much as people normally would just to maintain?

Dieting, as in restricting intake of calories, doesn't sound right. It's better to focus on in what form you eat those calories. Look at the Japanese, they don't go hungry and they don't get fat. They enjoy food. When I'm there I'm also slightly slimmer and I also enjoy eating the food. But when I'm in North America I'm starving - I can't find food that I want to eat. It's all highly processed junk food, burgers and greasy dressings and.. urgh. Local folks presumably know where to get edible foods, but travellers (for work or whatnot) don't.

Some people are just too "efficient" at converting food into calories. For these lucky ones they require less input.

Yes, but eating is something that people tend to enjoy doing. It means they can't do it as much, and can't consume what tend to be the tastiest foods and drinks without piling on tons of weight.

An average meal at a sit-down restaurant will be significantly over their daily calorie limit.

The lucky ones would be the ones who could eat as much as they like without becoming overweight.

There are medications to suppress appetite. There is no silver bullet for this affliction, though.

It's not just about appetite, it's about actually enjoying tasting food. Not to mention the social aspect

There are a few different types of weight loss surgery. None of them claim to change your metabolism, only stomach capacity (via stomach pruned to the shape of a hotdog) and / or nutrient absorption reduction (via intestinal wiring bypass).

This seems kind of like a "duh" nothing burger result.

Homeostasis is hard. But there is an upward notch effect: gain is easier than loss. Therefore it can both change, and asymmetrically.

A priori, there is no clear "it won't change" about how the body's homeostasis reacts hormonally to stomach size and rate of gastric function. Surgery has no good real life analogue in this case. How do we know what happens?. The evidence is valuable.

In a previous study (before surgery), Dr. Indelicato and his colleagues found that obese people had an average MF of 8.3 calories per pound, compared to 10.6 for overweight people and 12.8 for normal-weight individuals

This should be no surprise. An obese person has extra weight but it’s mostly adipose tissue which isn’t nearly as metabolically active as muscle tissue.

What is interesting is that, "even after weight loss surgery, a formerly obese person would need to eat far fewer calories than a normal-weight person in order to maintain their weight loss."

In other words the MF didn't change even after reducing adipose tissue!

This is a little bit surprising to me. Bodies consist of for example fat, organs, muscle, bone. I would expect that changing the proportion of body mass devoted to those by decreasing fat would change the metabolic factor, either up or down.

I would like to see the same study done with a drastic change in exercise and muscle mass.

I have always struggled with my weight. I find that the solution is always diet. Exercise does make me feel better, but doesn't seem to have much effect on my weight loss, if at all. At least in the short term.

I assume more muscle mass, would mean a higher resting metabolic rate. But how much. Is the effect large or small? Is it like this study, where sure it changes, but not enough to ever be able to eat like a "normal" person?

Diet is definitely the easier win. Working off a burger in the gym takes forever

In the short term, it is the easy winner. I'm just wondering if getting into much better shape has a large long term effect on the metabolic factor.

Wouldn't that be more efficient if you mamage to extract more from less?

Also, mechanical reduction in itself would not alter your gut biome, so why would they expect a change in efficiency?

Mounjaro is amazing. The GLP-1 agonists will change weight loss completely.

Doesn't do anything to boost your metabolism though. That is the second half of the magic pill we need. 1st a GLP1 agonist to reduce appetite and improve sugar sensitivity and 2nd something that safely and effectively increases metabolism towards but not exceeding nominal levels.

Maybe a growth hormone secretagogue or something that affects the mitochondria to make them less calorically efficient or something.

Agreed.

If you look at the Biggest Loser Study, their metabolism was horrible afterwards. They all ballooned back up. Wish they would have published thyroid test results, as I suspect the participants had wonky thyroids.

There’s some diet drug which does ramp the mitochondria up, but it works so well, people cook themselves, and now it’s illegal.

I expect I’ll be on Mounjaro either continuously, or for a month or two per year, every year for the rest of my life.

With Mounjaro, you can effectively fast for an entire day without much issue. Which reminds me, I haven’t had lunch.

However, I expect my metabolism is going down as I remain on Mounjaro, and when I stop, expect I’ll also rocket back up.

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