Your body needs some fat. It's necessary for cell membranes, to make steroid hormones, and to lubricate body surfaces. Fat also insulates your body from the cold. A little dietary fat is good because it helps your body absorb the fat soluble vitamins. But you don't need much fat -- about 20 to 35 grams per day is enough -- and many experts suggest avoiding foods that are high in fats.
Butter, margarine, vegetable oils, shortening and lard are nothing but fat, so foods that contain large amounts of these fats are going to be fattening too. That includes fried foods and baked goods like croissants and pie crusts. Snack chips, pork rinds and many frozen convenience foods are high in fat as well -- you need to look at the food labels to know for sure,
Meat can be high in fat, especially ground and processed meats like bacon and sausage. Red meats are particularly high in saturated fats. You can reduce some of the fat of certain cuts of meat by removing the visible fat. Some cuts of pork are high fat, but some, like ham, are lower in fat.
Poultry and Eggs
Poultry products, including turkey and chicken are lower in fat as long as you avoid the skin. Be careful with ground turkey -- it may be high in fat, unless the skin was removed prior to processing. Egg yolks are high in fat, but the whites are fat-free.
Dairy products vary -- butter is all fat, but non-fat milk contains no fat. Most lies in the middle somewhere. Most types of cheese are high in fat, except for dry cheese like Parmesan. Whipping cream and half-and-half are high in fat, as well. Yogurt is usually lower in fat.
Fish and seafood are lower in fat than most meat, but they can become high in fat if deep fry them in batter. Or if you add cream sauces or drench them in butter.
Nuts and Seeds
Nuts and seeds contain fats. And although they're healthier monounsaturated and polyunsaturated fats, the calories can add up quickly if you're mindlessly munching. Watch your portion size when you eat them.
Fruits and Vegetables
Most fruits and vegetables are low in fat, which is why they're low in calories. The two exceptions are avocados and olives -- they contain good fats, but they're higher in calories than most other fruits and vegetables.
Condiments and Extras
Salad dressings, creamed soup, gravy, cheese sauces, and desserts like ice cream are all high in fat unless they're specially formulated to be low in fat.
Institute of Medicine. "Dietary Reference Intakes for Energy, Carbohydrate. Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids." Accessed November 14, 2013. http://iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Macronutrients.pdf