Saturated fats raise our bad cholesterol, and are therefore considered 'bad' fats. These are found mainly in animal products like meat and dairy products as well as in eggs. If you are not vegan or vegetarian, then avoiding these fats is a little more difficult, but possible if you are vigilant about trimming visible fat off meat, and eating skinless poultry and healthier types of seafood.
Be careful with 'low-fat' dairy products, and check the labels carefully, as they often have added sugar to improve the taste.
An excellent source of fiber and energy, carbohydrates are an important part of a balanced diet. Refined carbs have had much of that goodness refined right out of them and retain empty calories with no nutritional value. Any white bread or goods baked with white flour, white pastas, sodas and most candy products contain bad carbs.