Low-fat snacks have to have three grams of fat or less per serving. So, yes, that’s just how much fat you’re getting -- unless you eat more than a single serving size, which is easy to do. That’s why some health experts argue low-fat foods are partly to blame for the fattening of America. The low-fat label, they claim, fools many of us into believing we can eat more. That's what researchers at Cornell University found in a recent study: People who thought they were eating low-fat cookies ate one third more than the people who were told they were eating regular cookies. What makes this label particularly dangerous to your diet is that low-fat foods often make up for their lack of fat with extra sugar and extra calories. In other words: Low fat does not mean low cal. In fact, it can mean the opposite.