Don't confuse eating healthy fats with your body fat! You need to eat healthy dietary fats every day! How much (or how little) body fat you have depends on how many calories you eat and burn every day.
At one time, health experts encouraged people to eat very little dietary fat to avoid "getting fat!" Of course, the issue is that maintaining your daily caloric surplus causes you to gain weight and fat.
First, you need fats (one of the macronutrients) in your diet for your body to function properly. Get about 20% of total daily calories from fats. Eat very little or no trans fats or saturated fats. Eating too many (and too often) trans fats and saturated fats will land you in the doctor's office with heart and cholesterol problems!
Focus mainly on eating heart-healthy unsaturated fats. Monounsaturated fats (MUFAs) can lower bad cholesterol (LDL) and lower total cholesterol. Good sources of MUFAs are nuts (especially raw), nut butters, olives, olive oil, avocados, safflower oil, peanut oil and canola oil.
Polyunsaturated fats (PUFAs) are also good for you---especially the omega-3 fats found in cold-water fatty fish like salmon, mackerel, herring, sardines, trout and white tuna. Flaxseed and walnuts are also good sources of omega-3 fats. Eat more omega-3 fats and less omega 6 fats. Too much omega 6 fat intake can lead to inflammation that causes arthritis, cancer and heart disease. Sources of omega-6 fats are soybean oil, sunflower oil, peanut oil, corn oil, sesame oil and cottonseed oil. Conjugated linoleic acid(CLA) fats found in red meat and dairy are also good for you provided they come from grass-fed cattle. Another option would be to supplement your diet with fish oil.
Limit eating saturated fats. Some sources of saturated fats are beef, poultry, pork, dairy, lard, cocoa butter, coconut oil and palm oil. Moderation is the key to eating saturated fats. Dark chocolate has become popular for its disease-fighting antioxidant qualities. So, I guess it would be a good "cheat food" (but not too much!).
Severely limit trans fats! Manufacturers of food love trans fats because they extend the shelf-life of food products and make them taste great! You've heard me say this--"if its fried, let it slide." Let these bad boys go too---fast foods, chips, cookies, packaged pastries, hydrogenated margarine and shortening. Some fast food chains have started to cut out trans fats. Check out their websites to see the nutritional breakdown of different restaurants.
Count the calories with fatty foods just like any other food. For example, nuts are good for you but they are loaded with calories. A handful of raw almonds will do the trick for you!