Trans fat ban: What you should know about healthy eating

Trans fats needs to be eliminated from U.S. food by 2018, according to a Food and Drug Administration deadline.

You can probably guess where they turn up: cookies, pizza, fried foods and potato chips. Physicians say trans fats are the most dangerous kind of fat you can consume.

But the ban won't be a health food magic bullet. MPR News' Kerri Miller talked to two nutritional experts about the latest FDA decision and how it factors into our current understanding of a healthy diet.

Trans fats: What you should know about the foods you consume

We started consuming more trans fats when the American diet turned away from meat and animal products.

Americans were told to avoid the fats found in animal products, but that didn't stop the demand for baked goods and other items that relied on ingredients like lard and butter, said Joanne Slavin, a professor in the Department of Food Science and Nutrition at the University of Minnesota.

Food producers started to make vegetable fats like Crisco out of corn and soy bean oil, creating trans fatty acid.

It's a cycle of "nutritional whiplash," she said.

"We decide there's one bad boy and we get after him," Slavin said. "That's the U.S. way of doing it. If you travel anywhere else in the world, they don't go there. They never did this. They never said, 'Let's get rid butter; let's get rid of meat; let's get rid of chocolate.' They just ate smaller amounts. Unfortunately we keep bumping around and outlaw something and then overreact in the other way."

Trans fats were also good for food companies.

"When we partially hydrogenate some of these vegetable oils, they become more shelf stable, which is a good thing for food manufacturers that don't want their products to spoil on the shelf, but a bad thing for our bodies because while they don't break down on the shelf, they don't break down for us," said registered dietician Victoria Jarzabkowski.

Trans fats are linked to a number of negative health outcomes, including heart disease.

"Trans fats aren't the only nutrient to blame for the obesity epidemic, but we know and we have really good evidence that's been mounting for years that trans fats do have a pretty deleterious health effect," Jarzabkowski said.

Artificial or synthetic trans fats, even in small amounts can increase your risk for heart disease and raise your bad cholesterol. Studies also show it can cause inflammation, hormone disruption and memory loss, she said.

Some nutritionists see the FDA announcement as an overreaction.

There are some products that naturally have some trans fats and can't be eliminated, Slavin said.

"That's the problem in nutrition," she said. "It's not possible. It's in butter, meat, yogurt, animal products. It can't go to zero, it's not humanely possible to get it to zero and even if it got to zero it wouldn't make us skinnier, less heart disease, more beautiful, smarter."

When in doubt, pick plant-based meals: Whole grains, legumes, vegetables and fruits.

Slavin and Jarzabkowski said it's all about moderation and making sure you get the nutrients you need. When you completely eliminate a type of food, like dairy, you need to make sure you're getting those nutrients somewhere else.

Weight loss is more about eating less, not exercise

Jarzabkowski said she is 100 percent behind a recent popular New York Times story about weight loss:

Think about it this way: If an overweight man is consuming 1,000 more calories than he is burning and wants to be in energy balance, he can do it by exercising. But exercise consumes far fewer calories than many people think. Thirty minutes of jogging or swimming laps might burn off 350 calories. Many people, fat or fit, can't keep up a strenuous 30-minute exercise regimen, day in and day out. They might exercise a few times a week, if that.

Or they could achieve the same calorie reduction by eliminating two 16-ounce sodas each day.