Sugar is bad news in pretty much every way. It can hamper the function of important proteins, it can lead to insulin resistance, and it causes inflammation that damages your arteries and your skin. You know about the obvious culprits, but sugar sneaks into many seemingly healthy foods. Energy bars have 30 to 50 grams of sugar and nonfat, fruit-flavored yogurt has 47. A teaspoon of sugar is equivalent to 4 grams, so that’s 11 teaspoons of sugar in a single yogurt—yikes!