For example, pizza, donuts, soda, cookies, etc. Cutting those foods in half alone will make a difference. After all, sometimes those bad foods are yummy foods. Another nutritional factor to consider is the quality of carbohydrates you eat. Carbohydrates are the nutrients responsible for giving your body energy.
Some carbohydrates do so better than others and some carbohydrates are more fattening than others.
Sugar would be the worst of these. There are also some carbohydrates that do not appear as sugar or taste like sugar, but can be almost as fattening as sugar. They are called high-glycemic carbohydrates. These foods include potatoes, corn, white bread or any refined grain, most cereals and white rice. You should replace these foods with the whole-grain versions.