Though it's important to keep your fat intake low, you will notice on the nutrition food labels the lower the fat, the higher the sugar. Sugar actually turns into fat. People get fooled into thinking it's better for them, but it's not always true. Try to eat things that are as close to natural as possible. Stay away from fast food places completely. It actually sounds like you're not eating enough calories during the day. For cereal in the morning make sure that it is something healthy with low sugar. For your sandwich, switch to 100% whole wheat bread. Eat tuna sandwiches(regular mayonaisse) with vegetables on it (I have pickles and pepperchinis and mustard) Try to eat your carbs (fruit, bread, cereal, milk) in the earlier part of the day. I am never hungry, with the way I eat. I make sure that I have lots of fruits and vegetables. I also change the kind of food I eat, so I don't get bored. Whatever you do, don't tell yourself you can't have this or that. Good that you eat that chocolate.