French fries are under attack again, this time by Consumer Reports. The magazine’s November issue says McDonald’s has yet to make good on its promise to reduce its fries’ trans fat by using a new oil. So, says the magazine, “its not too much of a stretch to say that fast-food fries are still swimming in ‘bad’ fat.”

The test-lab scientists for Consumer Reports ground up medium-size bags of fries from Wendy’s, McDonald’s and Burger King, extracted the fat, and analyzed it to determine the amount of “bad fats,” the combined total of trans fat and saturated fat. Both of those fats raise the cholesterol level and increase the risk of heart attack, but trans fat isn’t currently labeled and thus has been called the “stealth fat.” Trans fat, made by a process called partial hydrogenation, is created by bubbling hydrogen gas through vegetable oil. The process helps stabilize the oil, making it useful for deep-frying, and solidifies it for margarine and many baked goods.

Wendy’s had 7.5 grams of the total bad fats, McDonald’s had 10 grams and Burger King had 11 grams. Nutritionists say that on a standard 2,000-calorie diet you shouldn’t eat more than 22 grams of bad fats a day. A filmed report of the findings says, “That means if you eat a Big Mac or a Whopper with the medium fries, you’ve maxed out on bad fats for the day.”

As those tasty french fries develop a bad name, fast-food restaurants may follow McDonald’s lead and change cooking oils to minimize the bad fats. The potato industry has already noted a softening of the market for fries. Like the cigarette manufacturers, it is trying to offset losses at home by selling fries in foreign markets, especially China, Mexico and Indonesia.

That’s a poor solution. As other countries adopt American eating habits, the World Health Organization already has branded obesity a global epidemic. French-fry sellers would do better by offering more nutritious potato products than by exporting obesity to the rest of the world.