Actually, we know a great deal about weight gain in the micro sense that is explained by insulin. Jeez, point after point you've made are answered in that Taube youtube link in this thread. You could have your answers if you just clicked the link, opened your mind, and thought about what the guy said.
At the end of the day, here's what I know from going on and off low-carb eating for the last ten years.
I eat carbs, I crave carbs, I binge eat, I gain lots of weight. Contrarily: I stop eating carbs, I lose the cravings, I eat moderately, salads even look satisfying, I lose weight.
Ok, I'm not one for internet debates and I think this has run it's course fairly. Feel free to take the last word after this if you'd like.
Maybe we've been talking past each other or maybe you just see this differently than I do.
I see a difference between the physical mechanism of weight gain and the mental part of hunger and eating.
Your comment here is something I can totally agree with: When you eat carbs, you crave them and binge eat and over eat and gain weight.
For you, eating carbs leads you to increase your input too much. Now this could be insulin like you insist, or it could just be bad habit. Either way, it's what I consider "mental." Because even if blood sugar issues with carbs triggers the hunger, you're still choosing to satisfy it by eating.
But there's some basic science behind the thermodynamics of weight gain and weight loss that cannot be waved away IMO.
Also, worth noting that carbs do not trigger me to over eat. They are and have been a staple in my diet and I cut them from my lunch meal entirely for reasons of caloric restriction and eat them liberally at my dinner meal. I load UP on carbs at dinner. And still, I don't eat again for at least 18 hours.
At the end of the day, here's what I know from going on and off low-carb eating for the last ten years.
I eat carbs, I crave carbs, I binge eat, I gain lots of weight. Contrarily: I stop eating carbs, I lose the cravings, I eat moderately, salads even look satisfying, I lose weight.
Oh, for those of you who are fans of the Security Now podcast, Steve Gibson went into geeky detail in his switch to a low carb diet: https://www.grc.com/health/lowcarb-podcasts.htm