For years, nutritionists and doctors have preached that a low-fat diet is the key to losing weight, managing cholesterol, and preventing health problems. But more than just the amount of fat, it’s the types of fat you eat that really matter. Bad fats increase cholesterol and your risk of certain diseases, while good fats protect 
your heart and support overall health. In fact, good fats—such as omega-3 fats—are essential to physical and emotional health.A walk down the grocery aisle will confirm our obsession with low-fat foods. We’re bombarded with supposedly guilt-free options: baked potato chips, fat-free ice cream, low-fat candies, cookies, and cakes. But while our low-fat options have exploded, so have obesity rates. Clearly, low-fat foods and diets haven’t delivered on their trim, healthy promises.
Despite what you may have been told, fat isn’t always the bad guy in the waistline wars. Bad fats, such as saturated fats and trans fats, are guilty of the unhealthy things all fats have been blamed for—weight gain, clogged arteries, and so forth. But good fats such as the monounsaturated fats, polyunsaturated fats, and omega-3s have the opposite effect.As a matter of fact, healthy fats play a huge role in helping you manage your moods, stay on top of your mental game, fight fatigue, and even control your weight.
Types of dietary fat: Good fats vs. bad fats
To understand good and bad fats, you need to know the names of the players and some information about them. There are four major types of fats:
1.monounsaturated fats
2.polyunsaturated fats
3.saturated fats
4.trans fats
Monounsaturated fats and polyunsaturated fats are known as the “good fats” because they are good for your heart, your cholesterol, and your overall health.
Monounsaturated fat Polyunsaturated fat
Olive oil soybean oil
Canola oil corn oil
Sunflower oil safflower oil
Peanut oil walnuts
Sesame oil sunflower and pumpkin seeds
Avocados flax seed
Olives fatty fish (salmon,tuna)
Nuts (almonds) soy milk
Peanut butter tofu
Saturated fats and trans fats are known as the “bad fats” because they increase your risk of disease and elevate cholesterol.
Appearance-wise, saturated fats and trans fats tend to be solid at room temperature (think of butter or traditional stick margarine), while monounsaturated and polyunsaturated fats tend to be liquid (think of olive or corn oil).
Saturated fat Trans fat
High-fat cuts of meat Commercially-baked products
Chicken with the skin Packaged snack foods
Whole-fat dairy products Packaged snack foods
Butter Vegetable shortening
Cheese Fried foods
Ice cream Candy bars
Palm and coconut oil
How much fat is too much?depends on your lifestyle, your weight, your age and most importantly the state of your health. The USDA recommends that the average individual:
1.Keep total fat intake to 20-35% of calories
2.Limit saturated fats to less than 10% of your calories (200 calories for a 2000 calorie diet)
3.Limit trans fats to 1% of calories (2 grams per day for a 2000 calorie diet)
Simple ways to reduce saturated fat:
Eat less red meat (beef, pork, or lamb) and more fish and chicken
Go for lean cuts of meat, and stick to white meat, which has less saturated fat.
Bake, broil, or grill instead of frying.
Remove the skin from chicken and trim as much fat off of meat as possible before cooking.
Avoid breaded meats and vegetables and deep-fried foods.
Choose low-fat milk and lower-fat cheeses like mozzarella whenever possible; enjoy full-fat dairy in moderation.
Use liquid vegetable oils such as olive oil or canola oil instead of lard, shortening, or butter.
Avoid cream and cheese sauces, or have them served on the side.