I went to what was formerly the Netherlands Antilles (Bonaire), and ate a lot, inlcuding desserts every day. I did 2 or 3 dives a day (not too much exercise, actually). The food servings were smaller, less fatty, and much healthier. No sugared sodas, not much fried food, no fast food. I lost weight over an 8-day period. The Japanese also eat smaller portions, and while they eat high-salt diets, theirs is traditionally low-fat. They walk/ride the bike, and take public transportation, on the whole, driving little.
We (Americans), drive almost everywhere, walk very little, drink sugared sodas and coffee drinks, eat chips, snacks, prepared foods, fried foods, and do little exercise, as a whole. We depend on modern medicine to fix our ailments.
When I had high cholesterol a few years back, my doctor wanted to give me cholesterol-lowering pills. I asked him to let me try improving my diet and exercise more. He practically fell off his stool, but after raising his eyebrows, agreed. I was able to lower my cholesterol to acceptable levels for a while!
I don't really doubt the results of the study, knowing what I know, and having been to Bonaire and Japan. Just check out what people buy at COSTCO or the grocery store, on average, and you'll know the answer!