As Gov. Paterson renews his call for a sugar-soda tax to help curb obesity, and intends to take Mayor Bloomberg’s trans fat ban and fast food calorie counting crusade statewide, New Yorkers may have begun wondering, “Why us?”

After all, New Yorkers are not the fattest Americans. With a quarter of New Yorkers officially considered fat, the state ranks at No. 30. The state with the highest proportion – nearly a third – of obese Americans is Mississippi, according to the Centers for Disease Control and Prevention. Maybe Paterson wants to turn New York into the leanest state, a title currently held by Colorado (only a fifth of its population is fat).

But wait. Coloradoans have access to the exact same soda and the same hamburgers that New Yorkers and Mississippians enjoy – and no “sin tax” on them. This might be puzzling to those convinced that obesity is simply the result of eating too much, or the wrong things. Do people in Mississippi really have the biggest appetites?

Of course not. State-by-state obesity trends only make sense when you look at the other side of the obesity equation: physical activity. Simply put, residents of states with high obesity rates tend to move less.

On a recent visit to Colorado, Kansas’ Wichita Eagle food editor Joe Stumpe noticed that Colorado had all the usual fast-food eateries. So, he asked, why is the state leaner than Kansas (which ranks 19th fattest in the nation)? “[T]he answer,” Stumpe says, “does appear to involve walking, running, skiing, boating, biking and a host of other physical activities. Colorado residents just seem to be more active than people in a lot of other states.”

This observation was echoed by co-founder of the National Weight Control Registry, James Hill. He suggests that people’s failure to get trimmer can be attributed in large part to our narrow, food-only approach. “We focus too much on diet and not enough on physical activity,” he says.

Indeed, of the top 10 most obese states, government surveys show nine of them are also the most sedentary. The residents of the most obese state, Mississippi, report the lowest rates of leisure-time physical activity in the country.

Are fast-food outlets too numerous? Census statistics indicate that none of the top 10 obese states have the most fast-food restaurants per person. And seven out of those 10 “fat” states rank in the 15 lowest concentration of fast food. In fact, Mississippi is third lowest in the country in fast food density. Colorado, the leanest state, ranks in the top 10 in fast food concentration.

This reality is mirrored by scholarly studies. A 2007 study published in the International Journal of Obesity concludes, “The obesity epidemic is often speculatively blamed on fast food, when the actual evidence shows very little, if any, association of fast food with weight gain.” There is an unambiguous relationship between physical inactivity and obesity in the United States. At the same time, there is no clear relationship between obesity and access to fast food restaurants.

Paterson, Bloomberg and the rest of the food police don’t like those facts. Because controlling food prices or availability is easier than controlling people’s physical activity, they push for increasingly harsh measures, like taxes and junk food bans in schools.

If there’s a lesson to learn from Mississippi and Colorado, it’s this: Have a soft drink with lunch or a beer with your dinner – but don’t forget to go for a walk or run afterward. If they can do it in Denver, you can do it in New York.