As with carbohydrates, not all fats are bad, either. Dr. Sears correctly pointed out that some fats are actually essential for good health. It’s important to recognize a good fat and a bad one. The biggest public enemies in the fat world, according to Dr. Sears and most scientists today, are saturated fats and trans fats. Why are they so bad? For one thing, they cause inflammation in the body. But even worse, they cause the body to produce harmful compounds called eicosanoids, hormone-like substances that increase blood pressure and promote blood clotting (a prescription for stroke), and trigger inflammation in the arteries (a major cause of heart attack). To add insult to injury, eicosanoids make it difficult for the body to burn stored fat, promoting weight gain.
Unfortunately, many fast-food menu items contain massive amounts of saturated fat and trans fat. These fats not only pack twice the amount of calories as protein and carbs, but they also trigger an onslaught of free-radical molecules that damage the body’s cells and accelerate the aging process. That’s why it’s so important to think twice before you order—and learn how to eat healthier.
The good guys of the fat world are monounsaturated fats, which predominate in olive oil. They actually reduce inflammation and lower the risk of heart disease by not eliciting the insulin response and making it easier for your body to burn off its fat reserves. Whenever possible, you should substitute olive oil for any other fat or oil you are offered. One final point: you have to eat fat in order to lose it. Without sufficient fat intake, your metabolism can’t work properly. I’ll tell you more about these beneficial fats later on.
Is it really possible to lose weight by eating fat? Absolutely. In a landmark study conducted almost fifty years ago, people on a low-calorie diet, with 90 percent of the calories coming from fat, actually lost weight. When the same people switched to a diet consisting of the same number of calories coming from 90 percent carbohydrates, they failed to lose a pound. Just keep in mind that all fats, good or bad, have the same number of calories (9 per gram) so you never want to overdo it—especially at salad bars, where this is easy to do. In other words, don’t overdo it on the olive oil.