Any person that loses 10% their body weight through a diet is going to feel much better.
This seems... handwavey at best, do you know of any concrete ingredients with proven negative effects on the neurological system or is this pure conjecture?
The complex people have around weight I find really strange.
I'd be surprised if most of the mental health effects don't simply follow from the realisation that you are in control of your own weight.
Feeling powerless is pretty shit.
If you're obese, changing composition will likely add many health benefits, and very often the overall weight of the person shifting said composition will be lower because they were carrying a lot of fat, and only added a reasonable amount of muscle if they took up exercise.
Also, the vast majority of body builders are in “overweight”. Most muscle heavy gym goers should still be in normal BMI, or maybe the low end of overweight at a 10-15% body fat.
Should optimally be <0.5.
All in one weight in itself doesn't mean much in isolation. That's why you have people with a high BMI that are healthier than people with a "normal" one.
I suppose they could lose 10% through caloric restriction, but that wasn't part of this study.
>An athlete at 240 lbs
As a contrived example, somebody this big (athlete or not), is probably at an increased risk of sleep apnea. I know of some competitive athletes (with visible abs, no less) that were surprised to learn they have sleep apnea. After a CPAP they felt better. Alternatively, they could probably have lost weight (but no longer be as competitive in their chosen sport.) Some of the risk factors (gender, neck circumference) aren't the typical proxies we use to subjectively assess health as a layperson.
>That's why you have people with a high BMI that are healthier than people with a "normal" one.
This can be true, but it is not generalizable. Last I heard, something like 1% of people with a high BMI would fall into this camp.
Like, at some point, dying, lower heart rate, loosing hair, being cold, your weins collapsing, body eating own muscles.
Remember that pounds is a unit of force - not mass.
There's the set of "tech neck" images (example https://www.vital-balance.com/en/tech-neck/ though many more can be found) where it shows what the force on the neck is from the head. At 0°, it's 10-12 lbs of force down. If you've got your head tilted at 45° looking at a phone, the infographic says that its 49 lbs of force on the neck.
Additionally, when you walk or run you don't place only and exactly the force of the weight of your body down. Each foot is loaded with an impact and the forces are distributed up the leg. What your knee experiences is a dynamic and spiky load.
. . . "Our results indicate that each pound of weight lost will result in a 4-fold reduction in the load exerted on the knee per step during daily activities. Accumulated over thousands of steps per day, a reduction of this magnitude would appear to be clinically meaningful. " . . .
https://www.hsph.harvard.edu/nutritionsource/healthy-weight/
>There is increasing evidence that psychiatric diseases such as schizophrenia and bipolar disorder stem from metabolic deficits in the brain, which affect the excitability of neurons, Sethi said. The researchers hypothesize that just as a ketogenic diet improves the rest of the body’s metabolism, it also improves the brain’s metabolism.
I wouldn't be so quick to look for the most reductive/simple answer. Drastic dietary changes can have a huge impact on the microbiome, which can in turn lead to substantial changes in all kind of signaling between the gut and brain (in terms of hormones, immune molecules, neurotransmitter precursors, and much more). There may also be implications for cellular metabolism.
As the quote above touches upon, many mental health disorders may have a component of disruptions to metabolism and energy balancing on the cellular level. Possibly including ADHD, autism, treatment resistant depression, and OCD, in addition to schizophrenia and treatment resistant epilepsy.