I'm guessing the reason nobody runs these studies is that it's solved science?
https://www.sciencedaily.com/releases/2012/09/120912125114.h...
Also
>Basal Metabolic Rate (BMR)
What increases or decreases BMR?
E.g. https://www.scientificamerican.com/article/6-years-after-the...
Why are there very slim people who struggle to gain weight regardless of how much they try to eat more?
What causes hunger pangs for people when they have half a million calories strapped to their waist?
>I'm guessing the reason nobody runs these studies is that it's solved science?
Exactly this type of thinking has stymied research into very interesting questions.
One of the article's main points is that the obsession with the calorie-only model (with the assumption that it's solved) has stymied even asking these fat-metabolism questions in the first place (outside of veterinary science, where they actively trying to make animals that get fat very quickly).
But yes, your body is free to store/burn mass and energy in muscles, tissue, glycogen and whatnot if it chooses to store the excess at all.
Of course if you force an environment of extreme depletion (like bootcamp as mentioned elsewhere), you body will get to its adipose tissue, but that's not going to solve the obesity epidemic. Most veterans get just as fat as the rest of the population after they leave the service.
I personally can feel when my glycogen has been depleted when working out. Once it's gone I look a bit anemic and /pushing/ beyond certain limits becomes impossible. Normally it's a precursor to me entering ketosis, which pretty much guarantees I'll be burning fat or muscle only from then out.
Quoting: 'Similarly "[Obesity] is an energy imbalance between calories consumed and calories expended" is a fantastic definition of obesity.'
It isn't though: 'Obesity is a complex disease involving an excessive amount of /body fat/.' is how the Mayo cilic puts it.
Not all energy imbalances in either direction result in a loss or gain of /fat/, which is the point the article is trying to make.
I'll quote from the article: "Although researchers have rarely thought to control for energy intake in their experiments, when they did, testing whether their animals get fatter than lean controls even when eating as little or less food, they almost invariably report that they do. “These mice will make fat out of their food under the most unlikely circumstances, even when /half-starved/ [my italics],” as Jean Mayer wrote about obese mice he studied in the 1950s. This fundamental observation directly challenges the notion that obesity is caused by poorly regulated eating behavior."
Quoting again: "as if that means alcoholism isn't an intake problem"
Explaining why curing alcoholism isn't as simple 'stopping overdrinking' is just as tiresome as explaining why losing weight on a nationwide scale isn't as simple as 'eating less', as the article spills much ink to make clear.