Chapter One FATS AND FATOPHOBIA Eat less fat! You hear the message endlessly from doctors, nutritionists, and everyone else. It's repeated in every media story about diet and health, it's taught in schools, and it's been embraced by the food industry. Yet even as we're all supposedly eating less fat, more Americans are overweight-one in two adults, one in four children-than ever before. What's going on here? The problem is that the message is too simple. We're now in the grip of fatophobia-we see all fat as bad, no matter what. The truth about fat is far more complex. Eating fat doesn't necessarily make you fat, and not all fat is bad. In fact, there are some kinds of fat you have to have for good health.
A more accurate and helpful message would be: Eat more of some kinds of fats, less of others, and avoid one kind of fat whenever possible. Sure, it's a more complicated message, but it's also one that could help save your life. FAT FACTS A fat is any oily, organic compound that doesn't dissolve in water (just as oil floats on top of water) but does dissolve in oil or organic solvents. Chemically speaking, a fatty acid is made from a chain of carbon and hydrogen atoms-think of them as the building blocks of fat. (Later chapters on different kinds of fat go into this in a little more detail.) The natural fats we eat fall into three basic categories: 1. Saturated fats . These fats are solid at room temperature; butter, lard, and suet are good examples.
2. Monounsaturated fats . Liquid at room temperature, monounsaturated fats include olive oil and many nut oils. 3. Polyunsaturated fats . Polyunsaturated fats are also liquid at room temperature. Canola oil, safflower oil, corn oil, and many other widely used vegetable cooking oils are polyunsaturated fats. The oil found in fatty fish is also polyunsaturated.
Polyunsaturated fatty acids fall into two main groups: omega-3 fatty acids (alpha-linolenic acid) and omega-6 fatty acids (linoleic acid). These two types of oils are essential: You must have some in your diet for good health. Just as you have to get your vitamins from the food you eat, the essential oils also must come from your diet. THE UNNATURAL FAT The American diet today is on the low side for good fats, mostly because we eat a lot of a completely unnatural fat: trans fatty acids, or trans fat for short. Also known as partially hydrogenated vegetable oils, trans fats are vegetable oils that have been chemically modified to be more saturated. What makes trans fat so bad? Plenty. These unnatural fats raise the level of dangerous cholesterol in your blood, causing clogged arteries and heart disease. In fact, trans fats raise your cholesterol level about twice as much as saturated fat does.
Even worse, trans fats are so widely used in processed foods, fried foods, and fast foods that they're hard to avoid. Just check the ingredients list on almost any prepared or baked good and you'll see partially hydrogenated vegetable oil somewhere on it. The evidence against trans fat is now so convincing that the federal Food and Drug Agency (FDA) has announced plans to make food manufacturers list the amount of trans fats in their products on the food facts label. Chapter 5 explains the proposed labeling regulation and how it will help consumers avoid this deadly fat. CHOLESTEROL CONCERNS No discussion of dietary fat would be complete without a mention of cholesterol-even though this dreaded substance isn't really a fat at all. Cholesterol is a waxy chemical compound manufactured by your body. It's necessary for a variety of important functions, such as producing the hormones testosterone and estrogen and building cell membranes and brain and nerve tissue. Most medical authorities believe that high levels of cholesterol in the blood play a major role in causing clogged arteries and heart disease.
High blood cholesterol, in turn, may be caused by eating animal foods such as meat, dairy products, and eggs, which contain cholesterol. Although this connection has yet to be fully proved, current dietary guidelines suggest that dietary cholesterol should be limited to no more than 300 milligrams a day. Chapter 4 discusses the dangers and benefits to your health of dietary cholesterol. FATS ARE MIXTURES It's important to remember that every fat is really a mixture of saturated, monounsaturated, and polyunsaturated fatty acids. One type of fatty acid is generally in the majority, though, and the fat is classified on that basis. Butter, for instance, is put into the saturated fat category because it contains mostly saturated fat. Butter is 81 percent fat. (The rest is mostly water.
) One tablespoon (about 15 grams) contains 12.2 grams of fat, of which 7.6 grams are saturated fat, 3.6 grams are monounsaturated fat, and 0.5 grams are polyunsaturated fats. And because butter is a dairy product, it also contains 33 milligrams of cholesterol. So, a tablespoon of butter is more than half saturated fat, which is bad, but also has monounsaturated and polyunsaturated fats, which are good. And as Chapter 5 explains, think again before deciding margarine, which contains trans fats, is better for your health than butter.
It's also important to remember that every gram of fat, no matter what kind it is or where it comes from, contains 9 calories. For comparison, a gram of carbohydrates or protein contains 4 calories. Because a gram of fat contains 5 more calories than a gram of carbohydrates, in theory eating less fat means you eat fewer calories, which should in turn lead to weight loss. In practice, the opposite usually happens: To make up for the missing fat (and taste) in reduced-fat foods, manufacturers put in more sugar or other ingredients. The calories per serving don't decrease and you don't lose weight. In fact, you might gain, because you might start eating more calories. Why? You think that because the food has less fat, it's somehow more healthful and you can eat more of it. Also, fat in food plays an important role in satisfying your appetite and making you feel full.
With less fat in your food, you don't feel as satisfied and you eat more. More calories, even when they're low fat, means you will gain more weight. It's also important to remember that you need to have some fat in your diet for good health. Dietary fat is needed to carry vitamins A and E into your body, for example. You also need it for many other normal body functions. Body fat isn't the same as dietary fat. Simply eating a diet relatively high in fat won't necessarily make you gain weight; likewise, eating a low-fat diet doesn't guarantee weight loss. In fact, there's no solid evidence linking a high-fat diet with obesity or a low-fat diet with thinness.
Many people gain weight as they get older, for example, even as their intake of dietary fat remains the same. In the 1950s, most Americans got about 40 percent of their calories from fat. Today we get about 34 percent of our calories from fat on average, but we're fatter than ever-as mentioned, half of all American adults are now overweight. And contrary to popular wisdom, it is possible to be too thin. Your body's fat deposits are used not only as a nutritional storehouse but also to cushion your organs and keep you warm, among other functions. If your fat deposits drop below normal levels, it can cause serious health problems, such as irregular menstruation and infertility in women. RANKING THE FATS Here's how the fats rank in terms of your health: Polyunsaturated fats. Not only good but essential.
The omega-3 and omega-6 fatty acids are essential, meaning you need them to live and have to get them from your diet. However, not all polyunsaturated oils are equal, and getting the right balance of omega-3s and omega-6s is crucial to good health. Monounsaturated fat. Excellent. The best-known monounsaturated fat is olive oil, which has been shown to have a number of beneficial effects on health. Saturated fat. Bad-or at least not as good as monounsaturated or polyunsaturated fat. A substantial body of medical research suggests-but doesn't prove-that a diet high in saturated fats may lead to high blood cholesterol, which in turn leads to an increased risk of heart disease.
On the other hand, the link between saturated fat and heart disease isn't really as strong as many people think it is. The same is true for the link between a high-fat diet and some types of cancer, such as colon cancer, breast cancer, prostate cancer, and endometrial cancer. The evidence so far is suggestive but far from conclusive. Trans fat. Deadly. These fats raise your blood cholesterol-and the more of them you eat, the higher your cholesterol will go. Avoid them. Cholesterol.
Not good, but perhaps not as bad as you think. Like saturated fats, diets high in cholesterol are associated with high blood cholesterol and an increased risk of heart disease and stroke. Eating less cholesterol doesn't generally do much to lower your blood cholesterol, however. There's also some solid evidence that d.