It's nothing new to see Halloween under fire from religious fundamentalists who believe the day promotes devil worship, but now Oct. 31 has a new enemy: public health activists.

The notorious Center for Science in the Public Interest, the mother ship for food cops, has some advice to parents: Make sure to have carrot sticks and pumpkin seeds on hand. Dour dietitians warn about sugar, which some have taken to naming "poison."

It was really only a matter of time until America's overzealous "food police" took a grim view of Halloween.

It's a sign of the times that kids face overreactions to the idea of collecting boatloads of treats. But one night of candy and costumes isn't going to affect weight gain. Obesity can't be blamed on an occasional overindulgence, but rather overall lifestyle.

Recent research by Middle Tennessee State University economics professor Charles Baum and Lehigh University's Shin-Yi Chou examined a multitude of factors that affect weight to see what relative role they played in the rise in obesity rates.

The results might seem counterintuitive in a world where people are always pointing the finger at this or that: No individual factor contributed significantly to the national weight gain. The biggest factor — fewer people smoking — only influenced about 2 percent of the rise in obesity. Other factors, like less strenuous jobs, explained less than 1 percent.

Don't expect the blame-candy-first crowd to hoist a white flag, but the results of their failed policies are plain to see. Some school districts have taken an extreme position, going so far as to ban birthday cupcakes. But all that has accomplished is creating black markets for sweets. (One Texas observer wrote that the scene at a school was akin to "Willy-Wonka-meets-Casablanca.")

Focusing only on food will only set us up for failure. Kids are quite resourceful in avoiding blanket bans. Similarly, efforts to reform school lunches and engineer healthier eating (most notably on Jamie Oliver's TV show "Food Revolution") ran into roadblocks as kids simply brought less healthy meals from home.

Trying to change kids' tastes is an unrealistic strategy, but schools can help encourage better lifestyles by making sure that children burn off the treats they eat. The National Association for Sport and Physical Education reports that less than 10 percent of elementary, middle and high schools require a daily physical education class. The percentage of students participating in daily phys-ed was just 28 percent in 2003, down from 42 percent in 1991.

And schools are only one part of a child's life. While educators serve in loco parentis, kids have biological parents who can make sure they're learning good habits.

Parents, of course, should make sure that kids eat treats in moderation. And largely they already do: The average kid only gets 56 calories a day from candy, according to the federal government's 2010 Dietary Guidelines. That's less than a "fun size" Snickers, and it's not even in the top 10 sources of calories for kids.

And parents also need to make sure that this Facebook generation gets enough time being active. These days, that doesn't just mean kicking them out to the local park: British researchers recently reported that kids burned 150 calories per hour playing Wii games.

That's not to shill for the video-game industry — there are plenty of ways that gaming leads to hours on your duff. But given the number of options around us, does it really make sense to listen to the sour food activists who want to turn candy apples into forbidden fruit?