Are you suggesting that obesity makes a difference in the US but not in Europe? Or perhaps that obesity varies in the US but is uniform in Europe?
Whereas what the report finds is a flat line for Europe and a sloped graph (higher up) for the US.
So, if you don’t have insurance in the US and you’re in a poor neighborhood, then yes — you’re likely to have a lower standard of care.
But in Europe, everyone has state-provided insurance, and the quality of healthcare is much more consistent.
There could be multiple factors overlapping here though I suspect. For all but the richest, public healthcare helps, but for the richest the obesity gap closes any benefit in healthcare (diminishing returns in better care easily overshadowed by even slightly worse lifestyles).
I found this article (https://ourworldindata.org/us-life-expectancy-low) that shows a number of factors that contribute to the higher American mortality rate. Unfortunately it does not cover ALL causes of death, though if you want, you could independently investigate that[1]. Compared to Western Europe, Americans die at higher rates from smoking, obesity, homicides, opioid overdoses, and road accidents. There are two other graphed factors that don't have an option to compare with "Western Europe", but on those, it's relatively plain that the United States has a significantly higher infant mortality rate and significantly less access to healthcare.
And then there are suicide rates, which have increased some in the United States, but which are middle of the road compared to European countries (France is higher, Germany's about the same, Italy, the UK, and Norway are lower... I did not check these exhaustively). You'll have to click the button on the graph to change the country and then add up the rate by each age to get a comparison. I suppose the middle-range American suicide rate didn't fit the narrative of the article, but the author still wanted to highlight it as a concern given that it's been going up in the United States.
(Unfortunately, not every graph shows the same set of countries compared to the United States, which makes me think the author chose to cherry pick countries for specific graphs, and I'm not sure why, because it doesn't seem necessary. For example, the graphs in the article allow you to choose additional countries and sometimes regions to add to the graph; if I add "Western Europe" to each graph where it's an available option, the trends that the author is illustrating are completely preserved.)
The fact that Americans are so obese it’s draining down their lifespan in a collective way is still something that sounds worthy of study.
Regulation prevents market forces from correcting the gap. For example, insurance cannot charge higher premiums based on weight or lifestyle health status.