Like carbohydrates and protein, fat is a macronutrient, or a major source of energy that your body needs to stay healthy. Fat is a building block for cell membranes, hormones, brain tissue and healthy nerves and plays a role in muscle contraction and blood clot formation. Fat also helps your body absorb fat-soluble nutrients, including vitamins A, D, E and K. Because it’s the most calorie-dense form of energy, however, dietary fat is often associated with weight gain.
Calories in a Gram of Fat
One gram of fat provides 9 calories. So, a teaspoon of olive oil -- which contains only fat, no protein or carbs -- has 5 grams of fat and provides 45 calories. The amount of energy supplied by fat is more than twice the amount of energy provided by carbohydrates and protein, which each contain 4 calories per gram. Whole milk, which provides close to 150 calories per 8-ounce glass, contains significant amounts of each of the three macronutrients. Because it has about 8 grams of fat, the fat accounts for 72 calories -- or nearly half -- of the milk’s total calories. You can see how much fat is in a food product by checking its nutrition facts label, which lists the total amount of fat in grams, along with a breakdown of the types of fat it contains. All fat, no matter its type, supplies 9 calories per gram.
Recommended Daily Intake of Fat
Adults should aim to get 20 to 35 percent of their total daily calories from fat, according to the Food and Nutrition Board of the Institute of Medicine. So, an adult on a 2,000-calorie diet needs to consume between 400 and 700 calories from fat, or about 44 to 78 grams, of fat per day. The number of fat grams you need each day depends on your own calories needs, though, so it varies from person to person. If you only need 1,600 calories a day, you'd need fewer grams of fat as well: 36 to 62 grams.
This amount of fat provides appropriate levels of essential nutrients and is associated with a reduced risk of chronic disease. Not all dietary fats are created equal; however, while some fats are essential and some are considered healthy, others should be limited or altogether avoided.
Unsaturated Fatty Acids
Unsaturated fats -- including monounsaturated fat and polyunsaturated fat -- are generally considered good, or healthy fats, and should account for most of your daily fat intake. When consumed in place of saturated fat, unsaturated fats are known to help improve cholesterol levels and reduce your risk of heart disease. You can boost your intake of monounsaturated fat by snacking on tree nuts and peanuts, incorporating avocado into salads, sandwiches and other dishes, and cooking with vegetables oils. Corn, safflower and sunflower oils are also excellent sources of polyunsaturated fat.
Omega-3 fatty acids are an important type of polyunsaturated fat that, in addition to promoting healthy cholesterol levels, may help reduce blood pressure and lower triglycerides.To get your omega-3s, snack on wal nuts, stir ground flaxseed into everyday foods such as oatmeal or yogurt, or dine on salmon, sardines and other fatty fish.
Saturated and Trans Fats
Saturated fat mainly comes from animal-based foods, including high-fat cuts of meat, full-fat milk and yogurt, butter, cheese and other dairy products made from whole milk. It’s not limited to animal sources, however. Coconut products, palm oil and palm kernel oil are also sources of saturated fat. A diet rich in saturated fat may affect cholesterol levels and increase risk of heart disease, so the American Heart Association recommends limiting the amount of saturated fat in your diet to no more than 7 percent of your total daily calories. For someone on a 2,000-calorie diet, this amounts to a maximum of 140 calories, or 16 grams, of saturated fat per day.
Trans fat is a manufactured fat that’s created by adding hydrogen to vegetable oils to make them more shelf-stable. Although it’s been phased out of many processed foods, it can still be found in anything made with partially hydrogenated oils, which typically includes store-bought baked goods, snack crackers, frosting-in-a-tub friend foods and fast foods. Trans fat is the worst type of dietary fat and should be totally avoided because consuming even small amounts can promote inflammation, unhealthy cholesterol levels and insulin resistance.