Is grams of sugar included in the calories total?

I've been trying to count calories lately. Yesterday I was looking at cereal's, and I noticed that a healthier brand of cereal, like Cheerio's or something, has the same amount of calories as a more sugary kind, like CoCo Puff's. But the grams of sugar is where the big difference is. Cheerio's has like 3 grams, but Coco Puff's has 11. But they have the same calories total per serving. So I'm wondering how this works? Am I supposed to look at the calories AND sugar and somehow decipher if it's healthy or not?