Fat, fat, fat! Would all of our weight loss problems be solved if we just eliminated fat from our diets? Unfortunately, it's not that simple. We actually need fats -- can't live without them. Fats are an important part of a healthy diet: They provide essential fatty acids, keep our skin soft, deliver fat-soluble vitamins, and are a great source of energizing fuel. But it's easy to get confused about good fats vs. bad fats, how much fat we should eat, how to avoid artery-clogging trans fats, and the role omega-3 fatty acids play in heart health.
The U.S. Department of Agriculture's 2005 Dietary Guidelines recommend that adults get 20%-35% of their calories from fats. At a minimum, we need at least 10% of our calories to come from fat.
The problem is that the typical American diet is higher in fat: Roughly 34% to 40% of our calories come from fat. Why? Because they taste so good and are widely available in our food supply. Fats enhance the flavors of foods and give our mouths that wonderful feel that is so satisfying.
Does Dietary Fat Make You Fat?
You might assume that fat is to blame for the obesity epidemic now plaguing our nation. Actually, fat is only part of the problem. Obesity is much more complicated than just overeating a single nutrient. Eating more calories -- from fats, carbohydrates, protein, and alcohol -- than you burn off leads to weight gain. Simply put, people who get little physical activity and eat a diet high in calories are going to gain weight. Genetics, age, sex, and lifestyle also weigh into the weight-gain formula.
That said, dietary fat plays a significant role in obesity. Fat is calorie-dense, at 9 calories per gram, while carbs and protein have only 4 calories per gram, and alcohol has 7 calories per gram. It's easy to overeat fats because they lurk in so many foods we love: french fries, processed foods, cakes, cookies, chocolate, ice cream, thick steaks, and cheese.
Eating too much fat does more than expand our waistlines. Our love affair with fat has helped to trigger an increase in the rates of type 2 diabetes, certain cancers, and heart disease.
Basically, there are two groups of fats: saturated and unsaturated. Within each group are several more types of fats.
Let's start with the good guys -- the unsaturated fats. Unsaturated fats include polyunsaturated fatty acids and monounsaturated fats. Both mono- and polyunsaturated fats, when eaten in moderation and used to replace saturated or trans fats, can help lower cholesterol levels and reduce your risk of heart disease.
Polyunsaturated fats, found mostly in vegetable oils, help lower both blood cholesterol levels and triglyceride levels -- especially when you substitute them for saturated fats. One type of polyunsaturated fat is omega-3 fatty acids, whose potential heart-health benefits have gotten a lot of attention.
Omega-3s are found in fatty fish (salmon, trout, catfish, mackerel), as well as flaxseed and walnuts. And it's fish that contains the most effective, "long-chain" type of omega-3s. The American Heart Association recommends eating 2 servings of fatty fish each week.
The other "good guy" unsaturated fats are monounsaturated fats, thought to reduce the risk of heart disease. Mediterranean countries consume lots of these -- primarily in the form of olive oil -- and this dietary component is credited with the low levels of heart disease in those countries.
Monounsaturated fats are typically liquid at room temperature but solidify if refrigerated. These heart-healthy fats are typically a good source of the antioxidant vitamin E, a nutrient often lacking in American diets. They can be found in olives; avocados; hazelnuts; almonds; Brazil nuts; cashews; sesame seeds; pumpkin seeds; and olive, canola, and peanut oils.
Now on to the bad guys. There are two types of fat that should be eaten sparingly: saturated and trans fatty acids. Both can raise cholesterol levels, clog arteries, and increase the risk for heart disease.
Saturated fats are found in animal products (meat, poultry skin, high-fat dairy, and eggs) and in vegetable fats that are liquid at room temperature, such as coconut and palm oils. The 2005 Dietary Guidelines recommend limiting saturated fats to 10% or less of your total calories, while the American Heart Association recommends keeping them to just 7% of total calories.
The real worry in the American diet is the artificial trans fats. They're used extensively in frying, baked goods, cookies, icings, crackers, packaged snack foods, microwave popcorn, and some margarines. Some experts think these fats are even more dangerous than saturated fats.
"Trans fats are worse than any other fat, including butter or lard," says Michael Jacobson, executive director of the Center for Science in the Public Interest, a nonprofit advocacy group.
Research has shown that even small amounts of artificial trans fats can increase the risk for heart disease by increasing LDL "bad" cholesterol and decreasing HDL "good" cholesterol. The American Heart Association (AHA) recommends limiting trans fat to less than 2 grams per day, including the naturally occurring trans fats. The U.S. Dietary Guidelines simply recommend keeping trans fats consumption as low as possible.
It is recommended to read all labels. Look for foods that are low in total fat and well as in saturated and trans fats.