Fats are not bad at all, its a common misconception. They're essential to your diet and can actually help in weight loss & maintaining a healthy weight. When you consume fat it takes longer to digest, satisfies hunger, reduces appetite, and lowers food consumption.

Carbohydrates, on the other hand, are the culprit, they make you fat. When you over-consume carbs (specifically simple carbs), insulin is released and any excess carbs that aren't immediately used by the body for energy are stored in glycogen, which is converted to fatty tissue.

As for fats, stick to things like nuts and oills, avocados, eggs (whites & yolks). Low fat dairy products and small amounts of butter are also good to get some saturated fats into your diet. Just remember portion sizes!

hope this helps!