We used to think that eating any kind of fat was bad for your health. However, the pendulum is swinging the other way as we learn more about the health risks and benefits of different types of fat. We all need some fat in our diet. For example, fats are a necessary part of proper brain development in children under 2 years of age. This is the reason that very young children should drink whole milk instead of fat-free milk.
Our bodies are unable to produce certain fatty acids which are called essential fatty acids. The essential fatty acids are linoleic acid and linolenic acid. These are polyunsaturated fats. Because we cannot make these essential fatty acids, we must get them from our diet. However, most of us eat more fats than we really need and do not have to worry about a true deficiency.
Fat is nature’s way of efficiently storing energy or calories. 1 gram of fat has 9 calories compared to 4 calories in one gram of protein or carbohydrate. In other words, if you eat 1 gram of fat, you will get over twice as many calories as you would if you were to eat 1 gram of protein or carbohydrate. Therefore, we should still be careful about how much fat we eat because fat is calorie-dense.
We also need to pay attention to the type of fat that we eat. Fats are made of building blocks called fatty acids. There are different types of fatty acids such as saturated, monounsaturated, and polyunsaturated fatty acids. Some are healthier than others.
A fatty acid is made of a chain of carbon atoms surrounded by hydrogen atoms with some oxygen atoms on one end. The word “saturated” refers to the fact that the carbon chain has the maximum number of hydrogen atoms it can hold, which makes the carbon chain straight. Since the chains are straight, it is easy for the fatty acids to stack on top of each other. These straight chains are what allow the grease on pizza to become solid at room temperature and what we worry about clogging your arteries. Saturated fat can be found in items like animal fat, butter, palm oil, and coconut oil.
“Monounsaturated” means that the carbon chain has room for more hydrogen atoms which gives the chain a kink or a bend. Because the fatty acid is not straight, it does not stack as neatly. Polyunsaturated fatty acids have two or more kinks in the chain. If there are more kinks in the chain, it is more likely that the fat can stay liquid, making these fatty acids more healthy and reducing your risk for heart disease. Monounsaturated fats are found in olive oil, canola oil, nuts, and avocados. Fish and soy products are a good source of polyunsaturated fats.
The terms “omega-3” and “omega-6” just indicate where the first kink is on a fatty acid chain. For example, an omega-3 fatty acid has a kink at the third carbon. Fish, walnuts, and flaxseed oil are good sources for omega-3 fatty acids which are thought to reduce cardiovascular risk. In general, our diet today is relatively deficient in omega-3 fatty acids. Omega-6 fatty acids are found in corn and safflower oils.
Trans fats are made of unsaturated fats that have been processed so that they are not as kinked. This process gives the fat a longer shelf life which makes it attractive for establishments like fast food restaurants. Trans fats have been shown to increase the risk for heart disease. They can be found in margarine, shortening, commercial baked goods, and fast food.
Nutrition labels are very helpful in allowing us to figure out how much fat we are consuming and what kind of fat it is. While we should not avoid fats completely, we should monitor the amount of fat intake in the context of avoiding excessive calories. Of the fat that we do eat, we should make sure that more of it comes from the healthier types of fats and avoid trans and saturated fats.
Published On: June 28, 2006