Skinny people don’t always invoke jealousy. In societies where food is scarce, body fat is a sign of wealth, and overweight people are envied because their bodies show that they have enough to eat. In America today, of course, it’s those of us who get too much fat whose lives are in danger. But that doesn’t change the fact that some fat is necessary to stay alive.

Fat has many important roles in the body. For example, fat provides a highly-concentrated form of energy. One gram of fat gives you nine calories of energy, which is over twice that provided by carbohydrates and protein.

Fat also enables your body to transport, store and absorb the fat-soluble vitamins A, D, E and K. An absence of fat may mean a deficiency in these vitamins. Fat-soluble vitamins help to regulate blood pressure, heart rate, blood vessel constriction, blood clotting, and the nervous system.

Fat also provides insulation and a protective cover for vital organs. In an average adult, as much as 9 lbs of fat is found around the liver, heart, kidneys and other organs.

Essential fatty acids from omega-3 fats cannot be made by your body, and therefore must be supplied through your diet. Dull, lifeless hair and dry skin can be a sign that you may not be getting enough of these fats.

And of course, fat adds extra flavor, aroma, and texture to food, which is perhaps why we so often and too easily eat too much of it.

The right amount of fat keeps you alive; a high-fat diet, however, can increase the risk of heart disease and certain cancers. 

Most Americans consume over 40 percent of their daily calories from fat, which is far from the 20 to 30 percent they should be aiming for. This overload of fat leads to obesity and heart disease, as well as high blood-cholesterol and countless other health problems. The recommended 20 to 30 percent of recommended daily calorie intake from fat equates to about 30 to 60 grams for children and women, and 40 to 80 grams for teenagers and men, depending on activity levels. (Infants and children under three should not have fat intake restricted).

As well, less than 10 percent of total calories should come from saturated fats and/or trans fats. Cholesterol intake should be less than 300 mg a day. If you have high blood-cholesterol levels, you should aim for less than 200 mg a day.

Note: At lower calorie levels, the percent of fat calories should decrease to allow for protein calories (which have nutritional priority).