Body Fat – How Does It Affect Health?

Americans tend to consume about 34 percent of their calories from fat, even though most dietary recommenda­tions suggest we limit fat intake to 30 percent of calories or fewer. More specific recommendations by the American Heart Association (AHA) suggest that fewer than 10 percent of total calories come from saturated fats, 10 to 15 percent from monounsaturated fats (the kinds of fats prevalent in olive oil and canola oil), and about 10 percent from polyun­saturated fats (the main kind of fat in vegetable oils like corn oil and soybean oil). While the average overall fat intake common to the traditional Mediterranean diet is approxi­mately the same as that recommended by the AHA and oth­ers, the combinations and proportions of food in the Mediterranean diet suggest that an even lower percentage of saturated fats and a higher percentage of monounsaturated fats might be an even more preferable balance.

In either case, fat is a nutrient required by your body to stay alive. Many experts such as the World Health Organi­zation suggest that at least 15 to 20 percent of the total calo­ries you consume should come from fat to keep your body functioning properly.

Fat is a challenge for the weight-conscious, however. Consider that over half of all adult Americans are techni­cally overweight, and close to 25 percent are medically clas­sified as “obese,” according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), a branch of the National Institutes of Health. With obesity a national epidemic, don’t we have to be extra careful about the fat we eat, no matter what kind it is? Certainly, with 9 calories per gram (compared to only 4 calories per gram in both carbohydrates and protein), fat packs a caloric punch, and keeping caloric intake under control is important for health. According to the NIDDK, obesity not only increases the risk of many chronic diseases, including heart disease, diabetes, high blood pressure (which further increases the risk of heart disease), and even some cancers, but increases death risk by 50 to 100 percent!

Yet nutritionists know that the solution to obesity isn’t to cut out all fat. As much as our current culture looks askance at body fat, fat provides stored energy, available for when we need it most. Too much is harmful, but we all need some, and too little fat in the diet can be harmful, too, especially for children and women trying to become pregnant, and ac­cording to some researchers, an extremely low-fat diet is dangerous for everyone!

Your body needs fat for more than energy. Fat helps to keep your skin and hair supple and healthy, helps children to grow properly, insulates your body from temperature ex­tremes, and even protects your internal organs. Your cell membranes are composed largely of fat. Without fat, your body cannot absorb and deliver vitamins A, D, E, and K. And while your body makes certain fats, it must derive some from your diet. Two of these are essential: linoleic acid and linolenic acid. (These fats are called “acids” because fatty acids are what make fat.) Eating a variety of foods makes getting enough essential fat in your diet an easy task.

Fat takes longer to digest than other food types, so a meal with a sufficient fat content will generally satisfy your hunger longer than a low-fat meal, making fat (in modera­tion) an important weapon in the dieter’s arsenal. It can also make food taste better by adding flavor and texture. Have you noticed that nonfat versions of your favorite foods tend to be less satisfying than the “real thing,” even though many low-fat or nonfat foods dramatically boost the sugar content to make up for the lack of “fat flavor”?

Consequently, many low-fat and nonfat foods (such as a fat-free fig cookie) are as high or even higher in calories than the original higher fat version (such as a regular fig cookie). However, as we’ve mentioned before, engaging in a fat free-for-all makes it difficult to remain healthy and at an ideal weight. The point is that fat is necessary, but too much fat can compromise good health. A healthy portion of fat know-how will help you to include fat in your diet in a way that is beneficial, not destructive, to your health.

We know fat in the diet has been linked to an increased risk of heart disease, some cancers, and other chronic dis-eases. Too much dietary fat can also contribute to obesity, a risk factor in itself for a slew of health problems, including coronary heart disease and certain cancers. To understand why too much fat in the diet is dangerous to good health, let’s look at what excessive amounts of fat can do in the hu-man body.

A high-fat diet featuring foods from animal sources may result in an overconsumption of a particular kind of fat called saturated fat. Too much saturated fat can cause blood cholesterol levels to rise, increasing the risk of coronary heart disease. (Blood, or serum, cholesterol refers to the cholesterol in your bloodstream.) Foods high in saturated fatty acids include many types of meat, whole milk, lard, and butter, and a few plant foods such as coconut, palm, and palm kernel oil. Saturated fatty acids may soften at room temperature but still remain relatively firm instead of turn-ing to liquid (like a stick of butter left on the counter—more spreadable but still a solid, not a liquid).

Polyunsaturated fatty acids include vegetable oils like corn oil, soybean oil, sunflower oil, and safflower oil, and the fat in most seafood. Polyunsaturated fatty acids are liquid or very soft at room temperature. Some research suggests that excessive amounts of polyunsaturated fatty acids from these vegetable oils are linked to increased risk of cancer, but more research is required to confirm this. In the meantime, polyunsaturated fatty acids in moderate amounts may help to keep blood cholesterol levels low because they lower LDL, or “bad,” cholesterol levels. They also lower HDL, or “good,” cholesterol levels, however, making mono­unsaturated fatty acids an even better choice.

Monounsaturated fat is the fat type that dominates the tra­ditional Mediterranean diet. Foods rich in monounsaturated fatty acids include olive oil, canola oil, and most nuts and seeds. Liquid at room temperature, monounsaturated fatty acids in the diet have also been shown to lower LDL (“bad”) cholesterol levels, but not HDL (“good”) cholesterol levels in the blood, making it the fat of choice for a heart-healthy diet.

In other words, what you eat affects the amount of choles­terol in your blood. How much is too much? A serum cho­lesterol level above 240 mg/dl is considered high, and is associated with an increased risk of coronary heart disease. Between 200 and 239 mg/dl is considered borderline high, and below 200 mg/dl is considered desirable.

Cholesterol levels in the Mediterranean region during the 1960s were generally below 200 mg/dl. Although some of the diets in the traditional Mediterranean region were con­sidered high in fat (especially on the isle of Crete), the satu­rated fat component was low. Because olive oil was the primary source of fat and the use of animal foods was not high, saturated fat intakes were kept in check. Furthermore, with saturated fats low, the heart-healthy monounsaturated fats take center stage.