1. If you eat carbohydrates, you gain weight.
False: Those of us in the health and fitness field are thankful this myth has eased a bit since the "Atkins" craze. Eating too many calories makes you gain weight, not a particular type of Protein/Carbohydrate/Fat.
2. Don't eat after 6pm because you will gain weight.
False: Your body doesn't have a clock in it saying, "It's after 6pm so anything I eat now will turn to fat." Too many calories in a 24 hr period makes you gain weight. The largest meal of the day can be at 8pm at night as long your total calories for the day is less than you burn. Though you might not sleep that well!
3. Healthy fats are good for you and help with burning fat.
True: BUT healthy fats have calories too. Fat has over 2x's the calories than Protein or Carbs per gram. Eating a diet with healthy fat is good, but you want to limit the amount. For example 1tbs of olive oil has the same amount of calories as an apple and banana combined.
4. Whole wheat bread instead of white bread will help you lose weight.
False: This is one of my favorites. Everything has calories so it doesn't matter whether its from whole wheat bread or white bread. Whole wheat bread is healthier due the fiber content and may possibly help you feel "full" longer but it usually has more calories also. Watch those labels!
5. "My diet is very healthy so I should lose weight."
False: I hear this all the time. You can still gain weight eating healthy foods! Healthy foods have calories just like junk food, a calorie is a calorie. Ideally you would eat healthy foods and a low calorie diet. That is the recipe for success when trying to lose weight.