Why Is Processed Food Bad?
In two words: It's not. Or rather, not categorically.
"Processing is not always bad," says Jessica Fanzo, assistant professor of nutrition at Columbia University. "Often processing removes toxins or bacteria, or allows for us to eat certain types of foods in off-season due to freezing or canning." (Pasteurized milk, anyone?) Processing "can also include altering the consistency or taste of food to make it more appealing," Fanzo adds. So that delicious post-workout kale-celery-spinach-banana smoothie you had? Enjoy that virtuous feeling knowing that you were likely able to down that giant amount of greens because your treat was somewhat processed.
Still, even though pasteurized milk, kale smoothies, and instant oatmeal are all processed, that doesn't make them on par with doughnuts and Diet Coke.
"The key is to avoid foods that are 'ultra-processed,'" says Fanzo — basically, anything food-product-like or ready-to-heat.