Saturated vs Unsaturated Fat in Our Diet
We have heard it so many times that fat and cholesterol are bad for our health. Fat makes us overweight and may be linked to certain types of cancer. Too much cholesterol, on the other hand, can lead to a heart attack. However, there is good and bad news in this. Although we now have to worry about the kind of fat we eat, we do not need to eliminate every bit of it from our diet.
Our bodies need a reasonable amount of body fat and they manufacture it from a wide variety of nutritional substances, including proteins, carbohydrates and other fats we eat. Any portion of our diet not immediately needed as fuel will get converted into body fat. Since the fat from our food is the easiest part to convert, a high-fat diet is more likely to leave us with the extra pounds that we dread. That, however, is only one of the problems with too much fat in our diet.
How Much Fat Is Enough?
All fat is rich in calories. One gram of fat has more than twice the calories of a gram of protein or carbohydrate. In fact, a single tablespoon of corn oil is enough to meet our entire daily physiological requirement for fat. Many nutritionists believe that we should not get more than 30% of our daily calories from fat whereas the average Western diet gives us over 35% calories from fat. However, total intake is only one part of the story. There are many types of fat in our diet and not all fats are created equal.
Saturated versus Unsaturated Fat
Most of the fats we eat are triglycerides. Their molecular structure consists of three fatty acids attached to a glycerol molecule. These fatty acids vary in the extent to which they are saturated with hydrogen atoms. Saturated fats contain mostly saturated fatty acids whereas those with mostly polyunsaturated or monounsaturated fatty acids are known as unsaturated fats. Generally, the more saturated the fat is, the more likely it is to be solid at room temperature and the more dangerous it is for our health.
Because saturated fats tend to raise our cholesterol level, they represent the greatest threat to our heart. They are usually solid at room temperature. Saturated fats are abundant in whole-milk dairy products and well-marbled meats. Some vegetable fats such as palm, palm kernel and coconut oils are also mostly saturated. Whole milk, butter, cheese, ice cream, egg yolks and fatty cuts of pork, beef and lamb are all particularly high in these unhealthy fats. Because these are some of the most favorite components of any Western diet, we end up consuming two to three times as much saturated fat as we should.
Many nutritionists believe that if we substitute monounsaturated fat for the saturated fat in our diet, we can reduce our blood cholesterol levels and thus decrease our risk of heart disease. The best sources of monounsaturated fats are olive, canola (rapeseed), peanut, sesame, almond, avocado and certain fish oils. In Mediterranean countries, where olive oil is a significant part of the diet, people do in fact have fewer heart diseases. Experts think that up to 15% of our caloric intake should come from monounsaturated fats.
Fats from such sources as sunflower, safflower, corn and soybeans oils as well as certain fish can help reduce blood cholesterol levels and should make up 10% of our calories intake. The omega-3 oils, a type of polyunsaturated fat found in tuna, mackerel, salmon and other fatty fish, may act as a blood thinner, reducing the risk of developing lethal blood clots and potentially preventing hardening of the arteries. The most recommended way to get omega-3 oils is to eat two to three servings of fish per week. Fish oil capsules should be taken only with doctor’s consent.
Even though unsaturated oils seem to be better for our health, we should not make the mistake of adding more fat to our diet. Generally, the less fat we eat, the better off we are (but do not go to extremes as we need a certain amount of fat in our diet). Instead, switch from the more dangerous saturated fats to the more benign unsaturated types.
Many food manufacturers solidify liquid unsaturated fats through a process called hydrogenation. This method is used to make margarine or shortening for use in deep-fat frying or as an ingredient in candy and baked goods. However, a process called partial hydrogenation turns an unsaturated fat into a polyunsaturated fat containing trans-fatty acids (full hydrogenation turns it into saturated fat). Trans-unsaturated fatty acids are uncommon in nature and are only produced industrially. Some studies suggest that because they raise blood levels of the “bad” artery-clogging type of cholesterol, trans-fatty acids may increase our risk of heart disease.
The Best and the Worst Vegetable Oils
As it was mentioned earlier the lower the level of saturated fat and the higher the level of unsaturated fat (including both polyunsaturates and monosaturates), the better the oil is for our health. It is necessary to note that two of the so-called tropical oils – coconut and palm kernel oils – are even higher in saturated fat than butter. Canola (rapeseed), almond, sunflower and safflower oils are among the oils lowest in saturated fats. Olive, canola and almond oils happen to be the highest in monounsaturated fats, which are believed by nutritionists to lower the level of cholesterol in the blood without reducing levels of “the good cholesterol” HDL.