Here’s another reason why Manhattanites are skinnier than the average American — it’s harder to buy a snack here.

Manhattan shops are less likely to have candies, chips, sodas and other munchies at the checkout than stores elsewhere in the country, according to researchers at the Tulane University School of Public Health.

Nationwide, 41 percent of non-food stores stock the treats, but in Manhattan, just 32 percent do.

The upside is that Manhattan’s obesity rate is 16 percent, compared with 33 percent in the rest of the country.

Two extra snacks a week translates to 2,600 calories a year, or a pound of fat, the researchers said in a study published in the American Journal of Public Health.

On average, 95 percent of drugstores and gas stations nationwide sell snacks, as do 66 percent of hardware, garden and auto-repair shops, 39 percent of hair salons, 29 percent of bookstores and 16 percent of clothing retailers.