9 Foods You Should Avoid

Canned tomatoes

The red veggie is known as the best source of lycopene, an essential nutrient, but beware of the canned variety. All canned food contains the harmful chemical BPA, but it's especially concerning in tomatoes, whose acidity causes the BPA to cling on. "It's not the tomatoes that are bad," says Koch. "It's the way they're stored." If fresh isn't an option, look for tomatoes in glass jars or BPA-free cardboard containers.

Deli meats

Rethink tomorrow's low-calorie turkey and cheese sandwich. Salami, ham, roast beef and other deli meats are poor quality, packed with sodium, made from animals raised on hormones and antibiotics, and filled with nitrates. They may also contain chemical flavoring and dyes, so opt for fresh meat—like roast turkey or chicken—or wild-caught tuna-fish salad in your lunchbox.

Margarine

Unlike butter, which is made from animal products, margarine is created from vegetable oil. Its manufacturing process fills the spreadable stuff with trans fat, which increases inflammation by damaging the cells lining your blood vessels, upping your risk for cardiovascular disease, cancer, degenerative diseases, weight gain, and too-high bad cholesterol. "In my mind, it's one of the worst foods in the food supply," says Koch. "There's a common myth that healthy eating is equated with being vegetarian, and that's not necessarily true."

Vegetable oils

"You want your ratio of omega-6 fatty acids to omega-3 fatty acids to be about one-to-one," says Koch. "It's closer to 15-to-one in the American population." Today's highly refined vegetable oils, most often found in baked goods, are very high in omega-6 fatty acids, and are largely responsible for that unhealthy proportion. A lack of balance can lead to inflammation, so choose oils high in omega-3 fatty acids instead, like coconut, grapeseed and olive.

Microwave popcorn

Before you sit down for family movie night, pop a bowl of kernels on the stove, not in the microwave. The bag's liner contains PFOA, a proven toxicant and carcinogen in animals. When microwaved, PFOA clings on to popcorn, and preliminary human studies have linked the chemical to infertility, liver and testicular cancer.

Non-organic potatoes

It's unrealistic to purchase everything organic, but if you can swing buying a few foods that way, make spuds one of them. Although you're not told to eat organic potatoes after often as you are say, apples, it's just as important. "They're heavily sprayed and they're root vegetables, so they take up a lot of the pesticides and fungicides," says Koch. "They've been shown to have a high concentration of everything."

Table salt

No, a little salt sprinkled on your dinner won't do much harm, but when you choose table salt, you're missing out on healthy minerals found in sea, Himalayan and crystal salt. "Table salt is a refined product, so there aren't any nutrients in it," says Koch. "Our bodies need a lot of those trace minerals." Swapping in high-quality salt is an easy change to make, and from a cooking standpoint, significantly increases foods' flavor.

Soy protein isolate

There are two types of soy: whole soy—found in protein-packed edamame and soy nuts—and soy protein isolate, which is which is the highly refined, nutrient-stripped product found in foods like tofu, soy "meats" such as tofurkey, and soy milk. With soy consumption already unhealthily high in America, it's best to choose alternatives like coconut or almond milk and tempeh.

Artificial sweeteners

If you can't find it in nature, it's probably better to avoid it, which is why a half-teaspoon of sugar in your coffee, a dash of honey, or stevia are better options than a packet of Splenda. "Artificial sweeteners are so much sweeter—sometimes 200 times more so than table sugar—so the brain starts to crave sweeter foods," says Koch. Research is still out on whether artificial sweeteners, many of which contain aspartame, cause cancer and neurological programs, but science has confirmed that they spur weight gain and increase appetite.