The American Medical Association defines obesity as a disease. That means 35.7 percent of Americans -- those with BMIs over 30 -- are considered ill.

That's a lot of sick people.

Whether you agree with the AMA's decision or not, it underscores the gravity of the condition. The World Health Organization even considers it a global epidemic.

Worldwide, the relationship between wealth and obesity follows a positive trend: as wealth goes up, so too does obesity, according to Dr. James A. Levine of the Mayo Clinic.

In keeping with this trend, the United States is the wealthiest country in the world, and one of the most obese, at no. 18 out of 230 in obesity.

Within the United States, however, this relationship flips. Counties with lower average incomes tend to see higher rates of obesity. Though this obesity-income relationship seems quite paradoxical, explanations for it exist.

Lack of access to nutritious food and outdoor space for exercise are two of the more popular theories.

Some point to the geographic scarcity of grocery stores in many poor areas as a primary cause of the malnutrition, but this reasoning has recently come into question. A study done by researchers at the University of Pennsylvania, Princeton, and the U.S. Department of Agriculture found that differences in proximity of grocery stores explained less than 10 percent of the variation in healthy food consumption and that when new supermarkets opened, they had little effect on what nearby residents ate.

Though geographic accessibility of healthy food plays some (small) part in obesity, evidence suggests that household income is a more important factor. On a national level, the data shows that areas of high obesity rates tend to map similarly with areas of lower income.

Compounding the problem of accessibility is the fact that, as Dr. Levine pointed out in his paper, people in low-income counties also tend to exercise less. This may happen due to a variety of reasons. Most obviously, people with less money have a harder time affording athletic equipment, gym memberships and the like. Additionally, studies have found that violence increases when poverty does, which could potentially affect obesity by deterring people from exercising outside.

This in mind, the experts at HealthGrove, a health data analysis and visualization site part of the Graphiq network, looked at data from the Health Indicators Warehouse to find the county with the highest obesity rate in every state.