I think you're missing the insulin->carb cycle's effects, especially on people with metabolic syndrome issues.

Carbs break down to sugars which trigger the release of insulin. However, cells can become insulin resistant to varying degrees, causing their muscles and organs to reject the free-floating sugars in the bloodstream.

When that happens, your body fat gets to preferentially consume as much of the sugars as possible and then the kidneys filter out the excess. When this happens you end up with an undernourished body that doesn't process all of the calories in the food and that gains body fat preferentially to anything else.

That body fat then becomes a hormone regulator, affecting mood and energy levels even further.

There's so much that goes on in the body that isn't explained by calories in > calories out that, if not properly understood, can massively increase the difficulty of losing body-fat weight, (the body puts on fat over feeding its organs, the body doesn't get the nutrition it consumes to the cells that need it, the person is tired and eats too much to compensate, the list goes on I'm sure.)

Recognizing that not becoming overweight in the first place is the ideal solution, but failing that ideal solution the follow up isn't as simple as "don't eat so much" is a better approach to take. Medical science has not cracked the code yet, but I'm willing to bet that someday soon we will find a solution that breaks this cycle, and when we do obesity and overeating will drastically reduce so that only the people with mental or emotional overeating issues will remain in the obese category.

I was responding to the comment that metabolism is a “black box” that we can’t possibly understand, but metabolic syndrome is a good example of how we do understand metabolism including the exceptions.

Metabolic syndrome is a severe exception, though. It’s not something that happens to average people eating normal amounts of calories.

There are always exceptions in disease states, but those exceptions are invoked far too frequently in conversations about typical people on normal (not chronically hyper caloric or extremely sugar heavy) diets.

Anecdotally, I have metabolic syndrome, which is part of the reason why I am so interested in the process and issues surrounding it. My body naturally burns about 15% fewer calories than it should all things considered, I would have to exercise for about 30 minutes every day to equal the same caloric burn as a twin of mine without the issue's sitting on their butt all day.

Despite that, I've lost almost 100lbs from dieting (intermittent fasting, ECA stack, even Keto for a while) over the last several years but I'm still trapped by the condition as the less I weigh the worse the syndrome gets. Increased hunger, depression, lethargy, exhaustion, body temperature decreasing (painfully cold hands even in the middle of summer), insomnia, irritability, all of these issues hit me at the same time and get worse the lower my weight goes.

I don't have diabetes, blood sugar and a1c are normal, no hypertension (actually hypotensive), generally decent health otherwise. Diabetes and excess fat isn't the disease, it's the visible symptom of a larger issue caused by the American diet and lifestyle. Sure, it's my fault (and my parent's fault) that I became obese as a child but now the typical solutions for the issue simply do not work, and people who refuse to see that there is more going on than simply "fat pigs won't stop eating" do literally less than nothing to help solve or identify the core issues.

The food control / prevention of overeating solution works to prevent people from ending up like this, but rarely works to solve the issue once it has taken root, not to mention that the body typically doesn't lose fat cells once they have been created so even if you get to a normal weight you basically have a human fat cell parasite hungrily clawing at every morsel of food you eat more than what you immediately need permanently attached to your body unless you undergo surgeries to physically excise it from your body. (This is one of the reasons why most contestants on the Biggest Loser end up regaining their weight within a short amount of time, for instance. It's far easier to refill empty fat cells than it is for fat cells to be built by the body.)

This is why obesity is a crisis. Not just because of diabetes, but because the tools that we have to fight obesity once it arrives are insufficient for the job.

I recommend listening to this Dr. Peter Attica podcast. He explains what's typically going on with cases like yours at a cellular level, and then describes treatments that he has empirically found to work in his clinical practice.

https://peterattiamd.com/ama22/

>Evolutionarily, it wouldn’t make sense for our systems to evolve features that discard ingested calories or burn calories without good reason. Food wasn’t plentiful for the vast majority of our evolution.

I don't understand the argument. I agree with you that the human body seems to have several mechanisms (in terms of behavior changes) for reducing food consumption and/or up-regulating calorie expenditure to avoid gaining excess weight. And presumably there were excellent evolutionary reasons for humans to evolve these mechanisms, even though food was often in short supply! (As someone who has spent time trying to do physical activity while overweight, I can attest to this.)

But then you say that it wouldn't make sense for humans to evolve other physical mechanisms (such as changing digestion efficiency, fat storage efficiency) to accomplish those same well-motivated goals. Why not? I'm genuinely curious.

This study deals with the more subtle aspects of calorie expenditure though. What if eating another 300 calories a day meant your immune system was stronger and you recovered more quickly and you felt more excited and energetic, but it had no effect on your weight?