Health Statistics of 500 US Cities – Map and Sortable Table (opens in new tab)

And even if sugar were the main factor, OP's post would still be technically correct, because the underlying problem would be overeating foods with sugar, possibly in addition to overeating other foods.

This may be an unpopular view, but there's no getting around the fact that obesity in most adults is caused by poor decision making around food and exercise.

http://journals.plos.org/plosone/article?id=10.1371%2Fjourna...

Abstract

Western lifestyles differ markedly from those of our hunter-gatherer ancestors, and these differences in diet and activity level are often implicated in the global obesity pandemic. However, few physiological data for hunter-gatherer populations are available to test these models of obesity. In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size. The metabolic cost of walking (kcal kg−1 m−1) and resting (kcal kg−1 s−1) were also similar among Hadza and Western groups. The similarity in metabolic rates across a broad range of cultures challenges current models of obesity suggesting that Western lifestyles lead to decreased energy expenditure. We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences.

Obesity is literally impossible without being in a caloric surplus over the long term.

Added sugar contributes to the problem, in that it is not very satiating so it makes it easier to overeat, but you can easily lose weight on a high sugar diet so long as a caloric deficit is maintained.

The actual physiology is well-understood. The only problem is changing habits and behaviors, which can be difficult but is certainly not even close to impossible.

There was a study I'm struggling to find at the moment, that I saw via HN, that claimed childhood obesity is more dependent on what people eat than when they eat it or how much.

https://earthquake.usgs.gov/earthquakes/map/

Suffers from a few scaling pains.