PROVIDENCE, R.I. – Residents of much of New England – but not Maine – are fighting bulging waistlines better than people in other parts of the country, according to a state-by-state report released Monday by a national health advocacy organization.

Experts offer multiple reasons for why New Englanders are generally less obese, including a population that tends to earn more and be better educated; more walkable communities that promote outdoor exercise; and even a different approach to dining.

Massachusetts, Vermont, Connecticut and Rhode Island rank among the bottom six states in terms of adult obesity, each with rates under 21 percent, according to the survey from Trust for America’s Health, a Washington-based research group that focuses on disease prevention.

But in Maine, which the study said had the highest obesity rate of any New England state, the infrastructure is more rural and therefore less conducive to walking, said Dora Mills, the state’s public health director.

The survey rated obesity in all 50 states, plus the District of Columbia. It also looked at overweight rates among children ages 10 to 17.

Massachusetts had the second-lowest adult obesity rate behind Colorado, followed by Vermont, Hawaii, Connecticut and Rhode Island. New Hampshire, meanwhile, had the 38th highest rate in the country, while Maine ranked 33rd.

Exercise is a key component of fighting obesity, and New Englanders tend to walk more and depend less on their cars than people in other parts of the country, said Walter Willett, chairman of the nutrition department at the Harvard School of Public Health.

In Providence, a popular exercise path on the city’s East Side was crowded Monday morning with walkers and joggers, including Carmen Belgarde of Pawtucket, who was taking a brisk walk. The 66-year-old said she tries to exercise five days a week and the physical activity has been good for both her weight and her diabetes.

“It’s saving my life,” she said. “Let’s put it that way.”

Willett also cited differences in regional eating habits.

In the Midwest, for example, “a good meal is one where you stuff yourself so much that you have to loosen your belt and stagger away from the table,” he said.

In New England, there seems to be greater interest in quality over quantity.

The region also benefits from a relatively low poverty rate. People who are more affluent tend to have access to better health care and can more easily afford the higher cost of nutritious food, said Laura Segal, public affairs director for the Trust for America’s Health.

“Chips are a lot cheaper than pineapple,” she said.

Still, experts cautioned the report was nothing to celebrate as the rate of obesity increased slightly in every New England state but Vermont – where it remained consistent since last year. They said the region’s obesity rates were already too high and the difference between best and worst – Mississippi at 30.6 percent – was pretty small.

“What it looks like is if we continue on the same trends, we will be in 10 years where the rest of the country is now,” Willett said.

Gemma Gorham, nutrition coordinator for Rhode Island’s obesity prevention program, said she was troubled by the high percentage of low-income preschool children in the state who are either overweight or obese.

“We’re concerned that it’s still going up,” Gorham said. “Our first goal is to stabilize it – let’s stop the increase.”