- 13.2% of Americans have taken an SSRI in the past 30 days (https://www.cdc.gov/nchs/products/databriefs/db377.htm). To be clear, depression and torpor are different conditions, but it seems reasonable that a torpid-like state might include depression-like symptoms, and that those might be treatable with SSRIs.
First, I'm not sure there's a strong case that our lifestyles today are any more sedentary than in, say, the 1970s (when obesity rates were around 12% rather than 30%). We had cars, transit, elevators, escalators, school buses, television, keyboards, etc. in the 1970s, while at the same time "going to the gym" was just not something that average people did on a regular basis. Even going jogging was mildly eccentric.
Second, this is looking at resting metabolic rates, not overall calorie expenditure, although there is probably some association between RMR and physical activity.
Which brings me to the third point, which is that you're just shifting the burden of answering question of "why are we fat?" to "why are we sedentary?". If we are in fact increasingly sedentary, it could be that an outside factor is causing both low RMR and sedentary behavior. Anecdotally, I (as a comparatively skinny person) have a lot harder time sitting still than some of my friends and acquaintances that struggle with their weight. They might consider spending a day in bed as a great way to recharge, whereas it is something I would only do if I were pretty miserably ill.
I don't think any significant portion of the population is going to the gym regularly these days. There is definitely a fitness community, but most people just sit around and eat.
They will be in the coming decades as the population ages. The direct and indirect effects of sitting all day long are going to be incredibly costly to the society, and the only reasonable policy would be to combat our car addiction by any means necessary – and this is even distegarding all the other disastrous externalities of widespread personal car use!
I kind of wonder how much of a role climate control has to play as well. Surely must have a role alongside straightforward inactivity.. until pretty recently, people would burn a lot of calories just regulating body temperature indoors. People with outdoor jobs/lifestyles obviously still do.
- Basal metabolic rates in present-day Americans are substantially lower than they were in the past (http://webcache.googleusercontent.com/search?q=cache:nqBxKGn... -- Yes, the link is from the aforementioned blog, but you can check the citations).
- Mean body temperatures today are lower than in the past (https://www.vox.com/science-and-health/2020/1/22/21075218/no...).
- 13.2% of Americans have taken an SSRI in the past 30 days (https://www.cdc.gov/nchs/products/databriefs/db377.htm). To be clear, depression and torpor are different conditions, but it seems reasonable that a torpid-like state might include depression-like symptoms, and that those might be treatable with SSRIs.
- Obesity has absolutely exploded in the past 40 years, and none of the prevailing hypotheses have much explanatory power (https://slimemoldtimemold.com/2021/07/07/a-chemical-hunger-p...).