HFCS is notorious for the bad effects on the body, versus something like honey.
Same for the Intuit, simpler animal fats vs hydrogenated "trans" fats?
I feel like the key difference in their diets is it's not overly processed and full of things we've decided to put in there for cost reasons (corn subsidies making HFCS cheaper than cane sugar, and trans fats are cheaper than more expensive animal products).
As for HFCS, there's basically zero evidence that they're a major contributor to obesity versus other types of sugar. (In fact, honey consumed by the Hazda has almost the same balance as sugar as HFCS). We have multiple points of evidence to counteract this. 1) Mexico uses substantially less HFCS compared to other types of sugar, but Mexican obesity rates are as high as the US. 2) HFCS, and sugar in general, consumption has declined over the past 20 years. Yet obesity continues to increase. 3) HFCS was widely consumed in the 1980s, when the obesity rate was de minims.