Chewing the fat

Not all fat is created equal.

According to the American Heart Association, consuming a moderate amount of fat is essential for energy, nutrient absorption, hormone production and cell growth. The key is to understand what types of fats are healthy and which are less so.

"Fats have been demonized in our diets for the last several decades, but not all fats are bad," said Dr. Jeffrey S. Jump of the Center for Integrative Medicine.

The so-called bad fats, saturated and trans fats, raise low density lipid (LDL) cholesterol levels in the blood.

"When your cholesterol is high, it can cause blockage in the artery, which can lead to a cardiac event, or heart attack," said Indi Maharaj, a registered dietitian at Erlanger Hospital.

Saturated fats are typically solids (such as meats), many commercially produced baked goods and dairy products made from whole or reduced fat milk.

Trans fats (otherwise known as trans fatty acids) are created by adding hydrogen to liquid vegetable oils to make them into solids. The term "trans" is trendy now, but these fats are also known as "partially hydrogenated oils." Deep-fried foods, including doughnuts and French fries, are often fried in trans fats, but they are also contained in margarine, a product once thought to be a healthy alternative to butter.

"In the 80s we pushed margarine, margarine, margarine," said Maryann Davidson, a registered dietitian at Erlanger Hospital. "Then we discovered trans fats and how they can be just as bad as saturated fats."

Consumption of too many trans fats and saturated fats increases risk of heart disease, stroke and Type 2 diabetes, according to the American Heart Association.

Healthy fat sources, monounsaturated and polyunsaturated fats, can have the opposite effects, actually reducing LDL levels in the blood and helping with cell development. They also play a role in maintenance of healthy skin, cell development and hormone production. Monounsaturated fats are often high in the antioxidant Vitamin E.

According to registered dietitian Pam Kelle, many people who have a Vitamin D deficiency are on restricted fat diets, making absorption more difficult.

Monounsaturated fats are often plant derived. They can be found in avocados, vegetable oils (including olive oil, sunflower oil and sesame oil), peanut butter, nuts and seeds.

Polyunsaturated fats include omega-6 and omega-3, which are not naturally produced by the human body. Omega-6 and omega-3 play a crucial role in brain and body growth and development.

"The brain is all fat," said Dr. Jump, explaining why moderate fat absorption is essential for cerebral development.

Omega-3 fatty acids can decrease risk of arrhythmias, according to the American Heart Association and can decrease trigylceride levels.

Good food sources include fatty fish such as salmon, albacore tuna and mackerel. The AHA recommends eating at least two 3.5 ounce servings of fish per week.

Even healthy fats must be consumed in moderation in order to maintain weight. Every gram of fat, regardless of type, contains nine calories. Ms. Maharaj said no more than 30 percent of daily calories should come from fat and that less than 7 percent of caloric intake should be from saturated fats.

But don't be tricked into thinking heaping spoonfuls of all-natural peanut butter will help shed pounds.

"You're not going to lose weight switching from a candy bar to almonds," said Dr. Jump, but added that the fiber contained in healthy fat foods like nuts and avocado can help maintain a feeling of fullness.

"It's complicated, but they don't make you lose weight."