I doubt red meat is terribly unhealthy if not highly processed; and adding beans is probably more impactful than decreasing meat. I agree with what you are saying.
The role of exercise and calorie intake is a different complication; if I exercise I can eat more though do not always do so. Exercise can change calorie intake measures.
To return to this, as an aside.
Depends on the drug but most drugs that cause significant weight gain have that occur primarily because of what happens in the brain.
The brain works together with everything else l, communicates back and forth with the gut and its microbiome so on, but ultimately it is in charge of setting satiety and metabolism and movement. Of deciding the set point.
A variety of antidepressants and the atypical antipsychotics (used frequently to augment other meds or crudely as mood stabilizers) hit on the centers of the brain in charge and cause increase intake frequently while sometimes telling metabolism to slow down. Other brain active meds have the opposite effect, e.g. topiramate, and cause weight loss. I suspect these meds may impact how much people move during the day while not exercising as well, which is an under appreciated and variable part of calories out.
And some of us are more aware and mindful of our nutrition choices when we exercise. That said there is compensation that tends to occur that results in calories out with exercise not translating to the weight loss a straight forward calculation would make one think. Without thinking about it to some increase intake occurs even if one thinks they are eating the same. Activity when not exercising often subtly decreases. And while increase muscle mass burns more at baseline sometimes metabolism slows.
It is weird.
As you know I am marathon training. I am currently up to 30 to 40 miles a week plus some cross training. I am mindful of what I am eating and not eating more than my baseline to my sense of it anyway. Reasonable calorie out from exercise should be close to a pound per week.
Of course that isn’t what happens. I dropped down quickly to the weight I was when last doing endurance events and have then stayed there. Anchored.
Somehow my body, my brain in charge unbeknownst to my conscious awareness I suspect, is altering other variables to keep me where it, correctly I think, has as my right place when exercising. Getting to this weight just happened; losing more if I was someone wanting very low body fat percentage in search of a visible six pack say, an action movie star maybe, would be huge very difficult conscious effort if achievable by any means.
I am lucky. While I had gotten up to overweight I never hit obese therefore my brain has no problem adjusting back to a previous high end normal BMI set point. But the dead in the water stop I see is what happens to those who are heavier than I ever was too, at a higher point. Continuing the same calculated calorie deficit that had them losing before.
Yes. The body is much more complicated than a bomb calorimeter. Still whatever the brain sets as that point if it is there with that pattern of diet, exercise, and with a sense of social connections, it will be at good odds of better health outcomes.
(To bring this ramble back to Blue Zones!)