Wednesday, July 11, 2012

Fat

For decades, the belief that the more fat you ate, the more body fat you stockpiled was shared by many nutritionists. We became “fat obsessed,” and one trip down the supermarket aisle shows that we still are, with the preponderance of “fat-free” and “low-fat” items. Yet we are fatter than ever because these products may be low in fat, but they often are extremely high in sugar (to make them taste better) and thus calories, usually more than the full-fat versions that they are replacing.

Many followers of the low-carbohydrate, high-fat regimen have gone the way of the successful low-fat, higher-carbohydrate dieters: weight loss in the short term (due mostly to fewer calories), then dissatisfaction with the diet coupled with diminishing returns leading to millions of dropouts.

As a result, going in the opposite direction and eating more fat than normal to lose weight doesn’t work, either. One, fats are twice as calorically dense as carbohydrates or protein, so in general you want to limit your overall consumption. Two, fats are also downright dangerous, as excess fat consumption has been shown to increase degenerative diseases (heart and arthritis), cancer, vascular disease (kidney and liver failure as well as stroke), heart attack risk, and even acne. In particular, recent research implicates certain fats in the development of certain diseases. Saturated fats and
especially trans fats worsen your blood cholesterol levels and may pave the way to heart disease.

Saturated fats include mostly animal fats (such as meat, whole milk dairy, butter, and egg yolks) as well as certain plant food (like coconuts, nuts, and palm oil); they raise both “good” HDL and “bad” LDL cholesterol (high-density lipoproteins, or HDL, make it less likely that excess cholesterol in the blood is deposited in the coronary arteries, while low-density lipoproteins, or LDL, carry cholesterol from the liver to the rest of the body and may deposit it on the walls of these arteries). Trans fatty acids (like margarine and French fries) are worse because they not only raise bad cholesterol but also lower good cholesterol. Avoid trans fats under all circumstances. Some fats, meanwhile, can be good because they can actually improve blood cholesterol. These are unsaturated fats, including polyunsaturated and monounsaturated, that exist in plant sources like vegetable oils, nuts, and seeds. In addition, fats containing omega-3 fatty acids, like salmon and flaxseeds, are important; they make up nerve tissue, for example. Most American diets are woefully deficient in these fats, or even totally devoid of them. If you make sure to eat salmon, for instance, once a week that will usually be sufficient and eat unsaturated fats in moderation for flavor and satiation.

Good fat vs bad fat:

Saturated fats can lead to many health problems, so minimize the intake of them as much as possible. Meanwhile, use moderate amounts of unsaturated fats in your diet to help lower cholesterol and satisfy your appetite. Often, you can substitute the latter fats for the unhealthy varieties by using olive- or canola-oil spray for sautéing rather than butter (certainly you should never use margarine, unless it’s the kind you find at natural food stores that is unsaturated and is often bolstered by omega-3 fatty acids—ask for it).

Good Fats:

Monounsaturated: avocado, canola oil, all or the majority of peanuts, olive oil and olives, peanut butter and peanut the fats in certain nuts (almonds, cashews, pecans, and oil, sesame seeds, etc).

Polyunsaturated:

corn oil, cottonseed oil, soybean oil, sunflower oil, walnuts, pumpkin or sunflower seeds, mayonnaise, salad dressings, omega-3 fatty acids (albacore tuna, sardines, salmon, flaxseeds, etc.)
Bad Fats:
Saturated (eat sparingly): whole milk, butter, cheese, and ice cream; high-fat red meat; chocolate; coconuts; palm oil; poultry skin
Trans (avoid at all costs): most margarines; vegetable shortening; “hydrogenated” anything, even partially hydrogenated vegetable oil; almost all commercially prepared baked goods, margarines, snack foods, processed foods, and commercially prepared foods, whether at the supermarket or in chain restaurants (like French fries).

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