What I don't understand about your GLP-1 takes is that so much of fat activism and fatlib has been focused on emphasizing that fat people aren't fat because we eat too much and don't exercise (see the stereotype that we're greedy and gluttonous and lazy) and that many of us have tried starving ourselves before and it didn't make us lose weight and if we did lose weight it still didn't make us skinny. But people who take Ozempic to lose weight are getting skinny reliably while many fat people who are starving themselves aren't. So how does this work then if Ozempic really does just lower your appetite and that's the primary mechanism behind the weight loss? Like you can't tell me all those celebrities who were fat or chubby before and are now skinny because of Ozempic just didn't starve themselves hard enough before
I don't mean to sound accusatory because you seem way more knowledgeable about this topic than me. I don't know much about biology or medicine because I'm more focused on the social and political side of fat activism so I probably don't have an accurate understanding of it. I don't mean to say that you're wrong and fatphobic, I'm just trying to understand
weight science is really great at jumping wildly between a simple thermodynamic principle and a much more complex and half-baked set of moral and sociological arguments, and everyone who ever tries to talk about this makes the cardinal mistake of confusing linguistic transfer for conceptual commensurability, so let me try to speak more clearly.
humans gain weight when we take in more energy (calories) than we expend (burn). we lose weight when we take in less energy than we expend. these states are referred to as energy surplus/deficit, respectively, and they're the reason why a person who stops eating will lose weight, or why a farm animal confined in place and fed continuously will gain it. the reason this very reductive principle of energy balance doesn't translate simply into "you're fat because you failed at individual behaviour modification" is because both energy intake and expenditure are affected by a million other factors & biological processes beyond just what's on the plate and how much exercise we do.
on the intake side:
calorie counting is impractical to do with high accuracy, and even if someone has studied the food itself by methods like doubly labelled water experiments, what your digestive system actually does with it is a whole other idiosyncratic can of worms
hunger signals ramp up for a variety of reasons, including in response to the biologically threatening state of energy deficit & associated weight loss. this is often the mechanism behind weight cycling, often known as the restrict–binge cycle. hunger becomes, generally, more physically and mentally debilitating the more severe the energy deficit that prompts it. nb it's not actually that easy to eat past the point of satiety (& here i mean true satiety, not volume-eating temporary overfullness). hunger signalling is not just a matter of resisting a little treat every now and then -- it quite profoundly affects a person's overall ability to function and feel well. people who have not starved do not understand this, even if they say they do lol
more granularly, & although fatness is not a pathological state in itself, hormonal signalling can profoundly alter hunger, like in insulin insensitivity -- which is not a condition that develops as a result of eating sugar, but rather one that often drives sufferers to turn to quick energy like refined sugar because they are & feel ill
edge cases, like diseases that alter digestion, malabsorption, diseases that alter tissue catabolism, specific food allergies or enzyme deficiency intolerances, etc. nb if you added all these things together into one loose umbrella category, they ofc would not appear like edge cases so much as like a significant portion of any given human population
etc
on the expenditure side:
when we starve, a variety of biological processes will start, stop, or alter in response. many are hormonally mediated, like loss of dominant sex hormones due to pituitary overload/overproduction of 'stress hormones' -> periods stop, bone density decreases, etc. some are frank energy-saving mechanisms, like dropping body temp, blood pressure, and gut motility. over time that distinction tends to blur more, & that gradual shutdown of normal physical functions will reduce the overall caloric expenditure (this is what's referred to as a 'slowed metabolism') as well as make it immensely harder to engage in physically demanding activity even if you otherwise might want to
as with intake, measuring calorie expenditure is also just somewhat inaccurate inherently, due to everyone is different and formulas are just using variables like your weight or heart rate to estimate. this matters more or less depending on how much of your energy expenditure comes from activity (manual labour, endurance athletics, etc) vs background biological function maintenance, but, nb the state of exercise science is like comically somehow even worse than the scientific literature replication crisis standard. also in general almost everyone wildly overestimates how much energy exercise burns vs how hungry it makes you feel but whatever
again, edge cases, from metabolic disorders/diseases to chronic wasting eg secondary to certain cancers, variations in NEAT (hard to control consciously), disruptions to other bodily processes like eg an unrelated thyroid disorder dramatically raising or lowering energy expenditure in homeostatic maintenance like body temperature regulation, and so forth. again if you added these things all together it's not actually uncommon at all to be poorly accounted for in one way or another by 'standard' metabolic models
etc
what a glp-1 receptor agonist does, qua weight loss, is alter the complex hormonal pathways that regulate hunger, so that the person is no longer routinely hungry enough to maintain their previous weight, but a new lower weight. im assuming you the asker are familiar with 'set point' terminology: on a glp-1, your set point drops, and as long as you remain on the drug your body & hunger levels will generally defend the new lower set point instead of the old one. amphetamines suppress appetite, but only as long as you're actively on the dose; bariatric surgery makes eating enough physically impossible, but with generally a lot less dampening of the feeling of hunger, which is pretty horrifying. a glp-1 does some of the same delayed gut motility/stomach emptying, but this is secondary to decreased food intake rather than the cause of it, making it a generally less intolerable & more chemically sophisticated weight loss tool.
while you're actively losing weight, you will experience basically the same compensatory mechanisms that anyone in any condition of starvation would: hair falling out, gastroparesis, impaired circulation, fatigue, difficulty maintaining hydration, etc etc etc. but you won't feel enough hunger to need/want/be able to eat to your previous set point.
this^ is kind of what i mean by like... i think starving on a glp-1 just sucks lol, like experientially it seems shitter to me than free starving because you get something directly psychologically beneficial from the starvation itself, like every time someone describes taking these drugs it sounds like shit to me & almost everyone ive met who uses/used them ends up in some kind of on-and-off pattern with them bc they want the weight loss but everything else about them sucks and disrupts various other enjoyable aspects of their life. but i digress. again we've had plenty of other drugs that suppress appetite, but by different mechanisms that are not nearly as effective and generally come with a raft of pronounced adverse effects (eg, cardiac damage and insomnia with uppers, which really don't even have strong weight loss outcomes in the long term, you get the picture)
so. yes, in the most reductive sense, weight changes are always a result of an energy imbalance between intake and expenditure. that's kind of just basic thermodynamics, energy has to come from somewhere. at the same time, & i hope this is already clear from the above, our bodies are a lot more complex than just put in less food and try harder. most people do not actually find it crazy hard to drop a little bit of weight if they're coming from a state of relative energy balance: any chronic dieter can remember their first time lol. the compensatory mechanisms that subsequently drive regain and make weight loss harder (mathematically and subjectively), however, are in general vastly underestimated. this idea that anyone can be thin if they just try hard enough is like... anyone can climb a mountain, all you need is some shoes! *and also physical capacities some people do not have & tons of gear & guides & practice & money &
