That decline is an anomaly. The majority of it is attributable to covid, and a significant minority attributable to fentanyl: https://www.cdc.gov/nchs/pressroom/nchs_press_releases/2022/...
I do agree that the "rising tide raises all boats" rhetoric is largely bunk. But I don't think that this one particular measure, taken at an anomalous time, is sound footing for a counterargument.
Palm oil is in everything in the US, in France there's a lot more lighter oils and butter.
Obesity is a side effect of having so much food that calories are cheap and plentiful. That’s why obesity rates are rising everywhere in the first world. It’s also something virtually unprecedented in human history.
Btw obesity is rising in Europe as well.