I think we are getting caught up in the definition of "small". My original point earlier is that 400 calories is small compared with historical variation and variation among humans. Your original point is that 400 calories is more than enough to explain the weight gain and thus isn't "small". Those are different definitions of small, and are both true: 400 calories is small compared with historical and present variation among humans AND 400 calories is enough to explain the extra weight.

But the latter is obvious; clearly those 400 calories explain the weight gain, because people aren't suddenly metabolizing air or water or other calorie-free inputs into extra weight, those fat cells are creating fat from calories people consume. I suspect people are ascribing other claims to you because "400 calories is not small -- it's enough to explain the excess weight" is only a useful claim in this context ("this context" being "what causes obesity?") if you are also making the causative claim. 

You insist you are not making the causative claim -- so what exactly are you arguing re: the question of "what's causing the weight gain?"

I think you are missing my point -- which EY also makes above -- that you are concluding that the calorie consumption increase causes obesity when in fact none of the evidence you provide supports pointing the causal arrow in that direction specifically. 

We know obese people eat more, and we know that the greater fat mass has greater nutritional requirements.

The interesting question is not whether 400 calories are associated with the weight gain, clearly people are more obese now and also they eat 400 more calories on average, no one is disputing this. The interesting question is whether those 400 calories cause the weight gain or are caused by the weight gain. You are implying the former but there is not a lot of evidence in support of it -- and other posters in this thread are chiming in with other evidence suggesting that 400 calories daily is well within normal historical variation, which is SMTM's point that "400 extra calories causes weight gain" would be weird.

I didn't downvote you, I think you are eloquently arguing your point here! But I'm not entirely sure that the SMTM take is quite as bad as you make it out to be. 

An average of 400 extra calories a day isn't small on its own, but I think the SMTM argument is that it's small compared to historical variation in caloric intake, and small compared to variation among humans in general today. In other words: there were likely times and cultures historically where average calories consumed was higher or lower than today by more than 400 calories -- why wasn't there an obesity epidemic previously when caloric intake was higher? Why, 100 years ago, were not the people eating 400 extra calories a day all obese?

I clearly found it more a more compelling argument that you do. Like you, I read the SMTM contaminant argument as essentially saying "historically there has been some process that kept calories consumed and calories expended in relative sync; that process has been disrupted"—and the argument that "400 calories per day explains the weight gain" isn't really a counterargument to this?

I'll point out one more aspect that I think you may want to consider. You write: "to me it's quite obvious that in the long run more calorie intake has to lead to higher body mass" -- but this is a statement that is somewhat circularly derived from today's observations. 100 years ago, when very few people were obese, this statement might not be obvious at all. One might instead conclude that people with higher calorie intakes are compelled to burn more calories through manual labor, exercise, heat generation + sweating, etc.

Lastly, and obviously you know this on some level, but the fact that increased food consumption correlates with obesity, does not imply that that consumption causes obesity. SMTM argue that some external factor causes obesity; if so, increased food consumption would be a result of the body trying to maintain that weight. As you note, a 15% increase in body mass requires a 20% increase in caloric intake to sustain--if an external factor is increasing the lipostat, we would observe exactly what we observe today as well. It's dangerous to point the causal arrow in either direction without more evidence.

And, speaking of evidence: the overfeeding studies are interesting in part because they at least resolve the question of whether and how much short-term overeating causes body mass increases; you're 100% correct that they don't resolve the question of whether long-term overeating also causes body mass increases, and it would be super interesting to see if a long-term (say, 1 year) 400-calorie increase in consumption (that somehow doesn't come from changes in diet; maybe just eat an extra 20% at every meal?) causes weight gain. 

As far as I know, no one's run a long-term weight gain study—but we do have the super confusing result that a 30-40% decrease in calories is hard to sustain and the resulting weight loss plateaus at about a 10% decrease [0], suggesting that there's more going on than the simple linear relation.

[0] https://www.nejm.org/doi/full/10.1056/NEJMoa2114833

Because, those lawmakers you chose to bully were all vaccinated, so they were engaging in the exact same behavior you just criticized LA for trying to ban.

I don’t think Zvi was bullying them, more so just trying to highlight the hypocrisy of imposing mask restrictions on a population and then ignoring them yourself. It’s true that these particular lawmakers were not the same as the LA leadership, but the Democratic party as a whole is absolutely guilty of preaching/mandating one behavior publicly, and then privately flouting it themselves.

The real issue is that this kind of behavior makes the whole enterprise appear understandably suspect. Which is it: are masks necessary, in which case why are you taking a risk with your own life? Or are they unnecessary, in which case why are you supporting mandates? The conspiracy theorists‘ dream, really.