By COLETTE HEIMOWITZ
A controlled-diet study published in the journal PLOS challenges the theory that dietary saturated fat is bad or a contributor to heart disease. With that being said, there is an association between saturated fat in the blood and heart disease.
During the study, participants were put on six three-week diets that progressively increased carbs while simultaneously reducing total fat and saturated fat. Calories and protein remained the same. As carbohydrate levels increased, blood levels of a fatty acid (palmitoleic acid) known to increase the risk of heart disease and diabetes also rose steadily.
When palmitoleic acid increases, it's a signal that an increasing proportion of carbs are being converted to fat instead of being burned as fuel. In other words, the amount of carbohydrates you consume may determine how you process saturated fat -- whether it is burned for fuel or stored as fat.
How Much Fat Should You Eat?
A recent study in the journal Open Heart indicates that research does not support the original dietary-fat-consumption guidelines created in 1977 and 1983. These guidelines recommended that we cut fat to about 30 percent of our total daily calories and reduce saturated fat -- from red meat and dairy products like milk, eggs and cheese -- down to no more than 10 percent of total calories.
Suddenly people were avoiding fat and replacing it with sugars and refined carbohydrates -- often in the form of fat-free and low-fat packaged foods.
But these guidelines, intended to make Americans healthier, have done anything but. Adult obesity rates have doubled since 1980, and they're projected to increase by another 50 percent by 2030. Meanwhile, childhood obesity and diabetes diagnoses have tripled.
It's time to stop thinking of dietary fat as the enemy. In fact, fat is a key source of energy and essential nutrients. You can't live without it, and it might help you lose weight.
Fat, like protein, helps keep you full longer. And since it carries flavor, it makes food more satisfying. In other words, you could probably consume fewer calories of fat and feel more full and satisfied than twice the calories of refined carbs. Even better, when you eat fat, it slows the entry of glucose into the bloodstream, helping to moderate your blood sugar. So instead of that "crash and burn" after eating carbs, along with feelings of hunger soon after, fat helps control your appetite and your cravings. When more than half of Americans show some type of carb intolerance, it may make more sense to choose a diet that controls carbohydrates instead of restricts fat.
Here are the types of fat you should consume and one you should avoid:
Monounsaturated fats (MUFAs) are found in olive oil, canola oil, walnuts and most other nuts as well as avocados. MUFAs are usually liquid at room temperature.
Polyunsaturated fats (PUFAs) are always liquid both at room temperature and in the refrigerator. They're found mostly in oils from vegetables, seeds and some nuts. Sunflower, safflower, flaxseed, soybean, corn, cottonseed, grape-seed and sesame oils are high in PUFAs. So are the oils in fatty fish, such as sardines, herring and salmon.
Essential fatty acids (EFAs) are dietary fats that your body can't produce. Both omega-3 and omega-6 EFAs are PUFAs essential to your health and well-being. Omega-3s are found in the fat of shellfish and cold-water fish. Omega-6s are found primarily in seeds and grains, as well as in chickens and pigs. Unless you're eating a very low-fat diet, you are most likely getting more than the recommended amount of omega-6s.
Eat foods or take supplements rich in omega-3 fatty acids, such as shellfish, cold-water ocean fish and fish oil (salmon, tuna, sardines, herring and anchovies, along with non-fish sources like flaxseed, almonds, walnuts and canola oil). Avoid corn, soybean, cottonseed and peanut oils, which are all high in omega-6s.
Saturated fatty acids (SFAs) tend to remain solid at room temperature. Butter, lard, suet and palm and coconut oils are relatively rich in saturated fats. This type of fat is fine to consume on a low-carb diet, because when carbs are restricted, your body burns primarily fat for fuel.
Trans fats should be avoided at all costs. Trans fats have been associated with an increased heart-attack risk, and they have been shown to increase the body's level of inflammation. They are typically found in foods you should be avoiding already, including fried foods, baked goods, cookies, crackers, candies, snack foods, icings and vegetable shortenings.
--Colette
Readers -- Have you ever followed a low-fat or low-carb diet? Which method worked best for you and why? Do you try to avoid any fat
