From The Mayo Clinic's website:
Harmful dietary fat
The two main types of potentially harmful dietary fat:
- Saturated fat. This is a type of fat that comes mainly from animal sources of food. Saturated fat raises total blood cholesterol levels and low-density lipoprotein (LDL) cholesterol levels, which can increase your risk of cardiovascular disease. Saturated fat may also increase your risk of type 2 diabetes.
- Trans fat. This is a type of fat that occurs naturally in some foods, especially foods from animals. But most trans fats are made during food processing through partial hydrogenation of unsaturated fats. This process creates fats that are easier to cook with and less likely to spoil than are naturally occurring oils. These trans fats are called industrial or synthetic trans fats. Research studies show that synthetic trans fat can increase unhealthy LDL cholesterol and lower healthy high-density lipoprotein (HDL) cholesterol. This can increase your risk of cardiovascular disease.
Healthier dietary fatThe two main types of potentially helpful dietary fat:
- Monounsaturated fat. This is a type of fat found in a variety of foods and oils. Studies show that eating foods rich in monounsaturated fats (MUFAs) improves blood cholesterol levels, which can decrease your risk of heart disease. Research also shows that MUFAs may benefit insulin levels and blood sugar control, which can be especially helpful if you have type 2 diabetes.
- Polyunsaturated fat. This is a type of fat found mostly in plant-based foods and oils. Evidence shows that eating foods rich in polyunsaturated fats (PUFAs) improves blood cholesterol levels, which can decrease your risk of heart disease. PUFAs may also help decrease the risk of type 2 diabetes. One type of polyunsaturated fat, omega-3 fatty acids, may be especially beneficial to your heart. Omega-3s, found in some types of fatty fish, appear to decrease the risk of coronary artery disease. They may also protect against irregular heartbeats and help lower blood pressure levels.
While no specific amount is recommended, the guidelines recommend eating foods rich in poly and monounsaturated fats while staying within your total fat allowance. Most physicians and nutritionists recommend you limit saturated fat to no more than 10 percent of your total calories. Limit to 7 percent to further reduce your risk of heart disease. Based on a 2,000-calorie-a-day diet, a 10 percent limit amounts to about 22 grams of saturated fat a day, while 7 percent is about 15 grams. Saturated fat intake counts toward your total daily allowance of fat.
Need help calculating what your daily fat intake should be in grams? Multiply your daily total calorie intake by the recommended percentage of fat intake. Divide that total by 9, which is the number of calories in a gram of fat. For example, here's how a 7 percent saturated fat limit looks if you eat 2,000 calories a day. Multiply 2,000 by 0.07 to get 140 calories. Divide 140 by 9 to get about 15 grams of saturated fat.