I read in Everyday Life in Early America that 17th-century Americans were known for having bad teeth because of their easy access to sugar from the Caribbean and maple syrup from New England. I'm wondering if this early access to sugar played a role in why American food tends to be so much sweeter than that of other parts of the world, and if so, what other factors contributed to our collective sweet tooth?
At least part of the reason was demand for rum. Rum is made from sugar cane, which we imported from the Caribbean, distilled into molasses and rum, then exported out again. Manufacture of rum was early Colonial New England's largest and most prosperous industry.
I am sure there are others who could shed more light on this than I can, but I hope this helped. There is actually a really informative Good Eats episode (Pantry Raid X: Dark Side of the Cane, Season 12-Episode 15) which you might find informative.
When it comes to per capita consumption of sugar, the United States, at 30.5 kilos per person, doesn't look so bad. There are 28 nations with a higher per capita consumption of sugar. http://www.helgilibrary.com/indicators/index/sugar-consumption-per-capita This chart shows sugar consumption fell from more than 40 kilos per capita per year from 1960 to 1976, to the current level of 30.5 kilos per year in 2009.
However, this chart is just looking at cane sugar and sugar from sugar beets. After 1976, high fructose corn syrup became increasingly popular as a sweetener. In fact, American consumption of sweeteners from all sources has swelled to 61.9 kilos per year.