You may want to edit this comment. It reads as though you don't think Hispanics or Blacks count as American. I don't think you intend to express this racist sentiment, but it's easily inferred from the text as written.
I don't see how that sentiment can be read into what I wrote. I looked at three racial groups in America and observed they had different obesity rates. In abstract terms - "You think this quality is specific to the whole. If you divide the whole into three parts you can see the quality differs between the parts. This implies the quality is not specific to the whole."
To take that claim and infer that I mean to suggest the parts are not part of the whole is clearly nonsense.
There were 3 different responses that read your post similarly, as though the higher levels of obesity among Hispanic and Black people are unrelated to American culture, as though it doesn't matter what the rates of obesity are among people who aren't White.
I suppose the reason why some bristle at your partitioning of American obesity rates into racial groups is that it's unclear that it's particularly relevant. Obesity varies by income, urban/suburban/rural-ness, red state/blue state, and more.
Any of these dimensions could be used to partition America into tranches. Then, throw out the bottom tranches. Then, say that America isn't especially unhealthy.
Imagine person A says: There's an epidemic of gun violence in America.
Person B responds: No. Just ignore the urban gang violence, the mentally ill mass shooters, and the suicides. It turns out that among mentally stable Whites, America isn't that violent.
There could have been three million such responses. It still wouldn't change the fact that that's a logically incoherent reading of my comment.
The reason to use racial groups in my example, is first because I happened to know obesity differed between the groups, and second because it offers the opportunity to look at similar groups in different countries. This example shows that there is variance within the country and similarity beyond it, which I think makes a good case that the culture of the country is not what's responsible.
Regarding your point on violence, suppose it were the case that left handed people had a murder rate 100x higher than right handed people. Now, imagine too that the OECD countries, or whichever group you would like to compare America too, were 99% right handed and America were only 90% right handed.
Would it make sense in this case to say that American culture was the root of the problem with American violence if right and left handed Americans committed violence at the same right as their OECD counterparts? I wouldn't think so. I would think the explanation would be as simple as "greater proportion of more violent left handers".
I realize in the violence example that I've simplified and exaggerated the case compared to obesity. I am not claiming that obesity rates are similar to my example.
To take that claim and infer that I mean to suggest the parts are not part of the whole is clearly nonsense.