Four Tips on Thinking about Fat in Your Diet

Fat: It used to be the great American health problem, demonized by nutritionists and the food industry in the 1970s as “bad for you.” Solutions emerged in the form of fat-free diets and fat-free foods, which proliferated in the 1990s. But supermarket shelves stocked with Snackwells and other fat-free products did not lead to a healthier country.

“We distributed products that used the word ‘free,’ but they had a ton of calories,” says Dr. Wahida Karmally, director of the Bionutrition Research Core in Columbia’s Irving Institute for Clinical and Translational Research. As Americans replaced fat with carbohydrates, obesity rates increased. In the 1990s, the multi-center DELTA (Dietary Effects on Lipoprotein and Thrombogenic Activity) study conducted at Columbia and other universities in the US showed that fat reduction and increased carbohydrate consumption raised triglyceride levels and lowered HDL the “good” cholesterol levels in study participants.

As NPR’s The Salt blog reported last week, a more complex—and still controversial—portrait of fat has emerged in recent years.

Dr. Karmally offers guidance on how to safely incorporate fat into a healthy diet.

Take a Handful, Not a “Can-ful”

Many fatty foods, such as nuts like pistachios and almonds, are packed with wonderful nutrients; but they are also easy to snack on mindlessly. Be sure to control your portions so you don’t consume too many calories.

Learn to Read Labels

Trans fats raise the bad LDL cholesterol in your body and lower the good cholesterol. It’s important to know that when a box of cookies, for example, says “zero trans fat,” it does not mean that the product contains no trans fats. The labeling refers only to a single serving. That single serving may not have enough trans fat to be listed, but many people eat more than a single serving.

“People have to be educated about how to read labels and look at the ingredient list,” Dr. Karmally says. “If it has partially hydrogenated soybean oil, for example, it has trans fat.”

Another common confusion can occur when the label on a butter alternative says “no hydrogenated fat.” Let’s say the first ingredient is butter, and the second ingredient is palm oil. “This is as bad as putting beef fat on your toast,” Dr. Karmally warns, noting that palm oil is very high in saturated fat.

Be Wary of Fads Like Coconut Oil

Food fads come and go. Coconut oil, for example, has been touted for having health benefits that, Dr. Karmally points out, are largely unfounded.  While it’s been promoted as a medium-chain triglyceride (MCT), only a small percentage of the oil is MCT. This means that patients prescribed MCT oil should not take coconut oil as an alternative. And coconut is not a “healthy” fat in general. “I tell people that coconut slices are like a heart attack on a plate,” Dr. Karmally says. “Or a pina colada? A heart attack in a glass.”

One Diet Doesn’t Fit All

Eat the right fats in moderation, depending on your health status. If you have disorders of lipid metabolism or diabetes, you need to be extra mindful of fat in your diet. “We look at the whole person, so we can personalize nutrition recommendations,” Dr. Karmally says. “Just as we emphasize personalized medicine, registered dietitians/nutritionists provide personalized nutrition as medical nutrition therapy.”