When the fat is taken out, something has to go in its place, like carbs or sugar. That's just one of the lessons we need to learn about fat according to David Zinczenko, the author of Eat This, Not That. Another lesson: free food makes us fat. Every time you eat a free breadstick at the Olive Garden or a free cheddar biscuit at Red Lobster that's an extra 150 calories added to your meal. Eat a bowl of tortilla chips at the Mexican place and that's 450 extra calories. Extra calories are what make us fat. Another fat habit? Drinking soda. The average American drinks a gallon of soda every week, but studies have found that drinking only one or two sodas a day increases the risk of being overweight or obese by 33-percent. Here's a fat habit that seems counterintuitive: Skipping meals makes us over four times more likely to be fat. That's because when you skip meals, like breakfast, it slows your metabolism and boosts your hunger hormones. Finally, the combo meal makes us fat. That's because it's almost always more food than we need or would normally eat if we served ourselves. You're better off ordering the burger, if that's what you're really hungry for, instead of simply getting the fries and the drink too just because it's part of a pricing scheme.