Fat is one of the three primary nutrients that our bodies require to stay healthy. Fats serve a variety of short and long-term needs. In addition to carbohydrate and protein, fat can also be used by the body for energy. Some of the fat that we eat, gets used for energy in everyday living, the rest is stored in the fat cells. Stored fat serves to insulate the body, cushion vital organs and provide energy in emergencies. Fat also lends great flavor to foods and carries the fat soluble vitamins (A, D, E & K)
Of the three primary nutrients mentioned above, fat is the most concentrated source of calories in the diet, with 9 calories per gram (compared to protein and carbohydrate, each of which has 4 calories per gram).
How Dietary Fat Affects Blood Sugar
The main impact of dietary fat on blood glucose is indirect. Dietary fats slow digestion so when fat is eaten along with carbohydrates, the peak in blood glucose due to the carbohydrate, takes longer to appear and may last longer. For example, the peak in blood glucose after eating a plain baked potato might be 45 minutes, whereas the peak with a baked potato loaded with butter and sour cream might be about 1 hour. In addition, with the loaded baked potato, glucose levels may stay elevated longer. The best way to identify the effect that high fat foods have on your blood glucose levels is to keep food and glucose monitoring records and look for patterns.
Types of Fat
Fats come from both animal and vegetable sources in our food supply. Fats in the foods we eat are broken down into triglycerides. Triglycerides are the form in which fat travels throughout the bloodstream and are stored in fat tissue. There are three types of fat which triglycerides can be made up of. They are, saturated fat, monounsaturated fat and polyunsaturated fat.
- Saturated fats are hard at room temperature (fat on meat, skin on poultry, bacon drippings, cream, butter, shortening, palm and coconut oil) and are the least healthy of the fats because they increase the bad cholesterol (LDL) levels in the bloodstream.
- Monounsaturated fats are liquid at room temperature (olive, canola and peanut oils, avocado and nuts other than walnuts) and are the healthiest of the fats in the diet because they decrease bad cholesterol levels and increase good cholesterol (HDL) levels.
- Polyunsaturated fats are also liquid at room temperature and are healthier than saturated fats (corn, safflower, sunflower, soybean and cottonseed oil, walnuts). They decrease bad cholesterol levels (LDL), but also lower good cholesterol (HDL).
The polyunsaturated fat, fish oil, has received a lot of attention for its health-promoting properties. It is made up of omega-3 fatty acids which have a number of health benefits, including reducing the risk of heart disease. Eating fish is the best way to include omega 3's in your diet. High fat fish, like tuna, mackerel and salmon are rich in the omega-3 fatty acids.
Cholesterol is another type of fat in the diet found only in foods of animal origin (egg yolks and organ meats like liver, kidney and brain). Dietary cholesterol is not as well absorbed as dietary triglycerides. Ironically, dietary cholesterol does not increase blood cholesterol levels as much as do saturated fats.
How Much Fat Do I Need?
It has been known for some time that too much dietary fat contributes to health problems. Heart disease and excess weight top the list of potential problems. The recommended percent of fat that one needs depends on treatment goals for glucose, lipids (blood fats) and weight.
If weight and lipids are OK, people over age 2 should aim for less than 30% fat calories.
- The ideal distribution of fat would be less than 10% saturated, less than 10% polyunsaturated and 10-15% monounsaturated.
- Dietary sources of cholesterol should be less than 300mg each day.
If triglyceride levels in the blood are greatly elevated, more calories may be planned from monounsaturated fats and less from carbohydrates.