Some good news. Fruit is in, and French fries are out at most U.S. schools. That’s a start in trying to turn around the American obesity epidemic that has seen the percentage of obese children triple in the past 30 years.

A Centers for Disease Control and Prevention study found that only about 19 percent of schools served French fries last year. About six years ago, it was 40 percent. But the work isn’t done yet. Nearly 80 percent of high schools still sell sodas and sugar-filled fruit drinks, according to the CDC.

Meanwhile, the agency found that not nearly enough physical activity is offered to students during the school day — particularly in elementary schools, where just 4 percent offered daily P.E. classes last year.

But even if students eat only apple slices and celery in school, parents might want to think twice about stopping through the fast-food restaurant for an after school snack.

MSNBC.com reports that in the last few years, Hardee’s, Burger King and Wendy’s have introduced 1,000-calorie-plus sandwiches stuffed with 12 ounces of beef — the amount of meat recommended for two days for most adults. And current fast-food servings are as much as five times larger than in the 1950s. McDonald’s original soda was 7 ounces. Today, a small is 16 ounces, and a large is twice that.

The problem, it seems, is that people tend to eat or drink what’s in front of them.

But before you scoff at your over-indulging brethren for failing to just say no to the double Whopper or the Baconator, note that a British government thinktank called Foresight said this week that the obesity problem is bigger than a lack of individual self-control.

Weight gain does not result from overindulgence or laziness alone, according to a Reuters news service story on the British report.

Foresight found that the technological revolution has conflicted with our biological makeup and made weight gain unavoidable for much of the population. Foresight was talking about the British population, of course. But the same theory could be applied here.

Bottom line, we eat too much high-calorie, processed food, and we don’t move around enough. But it’s not JUST our fault. Blame it on society.

Meanwhile, eat a carrot and run around the block. And take your kids with you.