Fat tastes good. Maybe that's because when our species had to fight to find enough food in the early days of our evolution, eating a lot of fat made sense since it contains the most calories of the three major foodstuffs. Now the pendulum has swung the other direction, and people today have too many calories available to them.

Obesity, diabetes, and clogged arteries are the predictable by-product of a high-fat diet. The average diet of a person in the United States derives 37 percent of its calories from fat. A well-balanced diet should contain 30 percent or less.

As important as the total amount of fat in the diet is its source. Fats found in meats and dairy products raise your cholesterol. Fats from plant sources, such as olive oil, lower your cholesterol and are sometimes referred to as "good fats."