Chapter 5. Lipids
The Role of Lipids in Food
High Energy Source
Fat-rich foods naturally have a high caloric density. Foods high in fat contain more calories than foods high in protein or carbohydrates. As a result, high-fat foods are a convenient source of energy. For example, 1 gram of fat or oil provides 9 kilocalories of energy, compared to the 4 kilocalories found in 1 gram of carbohydrate or protein. Depending on the level of physical activity and nutritional needs, fat requirements vary greatly from person to person. When energy needs are high, the body welcomes the high-caloric density of fats. For instance, infants and growing children require proper amounts of fat to support normal growth and development. If an infant or child is given a low-fat diet for an extended period of time, growth and development will not progress normally. Other individuals with high-energy needs are athletes, people who have physically demanding jobs, and those recuperating from illnesses.
When the body has used all of its calories from carbohydrates, fat usage becomes the predominant energy source. A professional swimmer must consume large amounts of food energy to meet the demands of swimming long distances, so eating fat-rich foods makes sense. In contrast, if a person who leads a sedentary lifestyle eats the same high-density fat foods, they will intake more fat calories than their body requires within just a few bites. Use caution—consumption of calories over and beyond energy requirements is a contributing factor to obesity.
Smell and Taste
Fat contains dissolved compounds that contribute to mouth-watering aromas and flavours. Fat also adds texture to food. Baked foods are supple and moist. Frying foods locks in flavour and lessens cooking time. How long does it take you to recall the smell of your favourite food cooking? What would a meal be without that savoury aroma to delight your senses and heighten your preparedness for eating a meal?
Tools for Change
There are many sources of omega-3 foods. It is important to strike a proper balance between omega-3 and omega-6 fats in your diet. Research suggests that a diet that is too high in omega-6 fats distorts the balance of proinflammatory agents, promoting chronic inflammation and increasing the risk of health problems such as asthma, arthritis, allergies, or diabetes. Omega-6 fats compete with omega-3 fats for enzymes and will actually replace omega-3 fats. The typical Western diet is characterized by excessive consumption of foods high in omega-6 fatty acids. To gain a proper balance between the two, increase your omega-3 fat intake by eating more fatty fish or other sources of omega-3 fatty acids at least two times per week.
