Ask the Experts: Healthy Fats

Wow! What a relief this one is! The jury is in on “no fat” diets…they don’t work! This is really no surprise considering the US population has gotten 10% more obese since the arrival of all the low fat/no fat products in the 1980s and 1990s. Take a look at the following Q&A article from Harvard.

Harvard School of Public Health asked Dr. Walter Willett of Harvard School of Public Health and Amy Myrdal Miller, M.S., R.D. of The Culinary Institute of America to explain why it’s time to end the “low fat is best” myth—and to provide ideas for how to use healthy fats in the home kitchen.

Should I ditch a low-fat diet?

Walter Willett: If you’ve been able to keep your weight, blood cholesterol, and blood glucose under good control while eating a low-fat diet, this type of diet may be working for you. But for many people, low-fat diets don’t work. In fact, dozens of studies have found that low-fat diets are no better for health than moderate-or high-fat diets—and for many people, they may be worse.

Low-fat diets are usually high in carbohydrates, often from rapidly-digested foods such as white flour, white rice, potatoes, sugary drinks, and refined snacks. Eating lots of these “fast carbs” can cause quick, sharp spikes in blood sugar and insulin levels, and over time can increase the risk of diabetes and heart disease. High-carbohydrate, low-fat diets also have a negative effect on the fats and cholesterol in our blood: They raise “bad” blood fats (triglycerides) and they lower the “good” blood cholesterol (HDL), both of which can increase the risk of heart disease. These diets also tend to increase blood pressure.

For many people, low-fat diets are not satisfying. People finish a meal and within a few hours, they are hungry again, seeking more low-fat fixes for their hunger. This vicious cycle leads to weight gain and, in turn, to the conditions associated with excess weight (such as blood triglycerides, low HDL cholesterol, high blood pressure, and diabetes).

Are “fat free” foods healthy?

Amy Myrdal Miller: Some foods in their natural state contain little or no fat—for example, most fruits, vegetables, whole grains, dried beans. And of course these are healthy choices. But processed foods billed as “low fat” and “fat free” are often higher in salt, sugar, or starch than their full-fat counterparts, to make up for the flavor and texture that’s lost when food manufacturers slash fat. So they are not necessarily “healthy” choices. For example, low-fat and non-fat salad dressings are nearly always higher in sugar and salt.

Will eating fat make me get fat?

Willett: No, it’s a myth that eating specifically high-fat foods makes you fat. Eating or drinking more calories than you need from any source, whether it’s fat, carbohydrate, protein, or alcohol can lead to weight gain. Over the past 30 years in the U.S., the percentage of calories from fat has actually gone down, but obesity rates have skyrocketed. Sugary soft drinks don’t contain any fat—yet the billions of gallons of sugary beverages that Americans drink each year have been a major contributor to the obesity epidemic.

Can I lose weight on a low-fat diet?

Willett: It’s possible to lose weight on any diet. But carefully-conducted clinical trials find that following a low-fat diet doesn’t make it any easier to lose weight or keep it off. In fact, study volunteers who follow moderate- or high-fat diets lose just as much weight, and in some studies a bit more, as those who follow low-fat diets.

Calories are what count for weight loss, so it’s important to find a lower-calorie eating plan that you can follow—and a lower-calorie plan that’s good for lifelong health. Low-fat diets raise triglycerides and lower good cholesterol, so for many folks, they’re simply not the best choice for health. For some people, high intake of carbohydrates, particularly if they come from refined rather than whole grains, can make weight control more difficult.

Are all kinds of fat equally healthy?

Willett: Some types of fats are healthier than others. Unsaturated fat is the healthiest type of fat. Plant oils, such as olive, canola, corn, peanut and other nut oils; nuts, such as almonds, peanuts, walnuts, and pistachios; avocados; and fish, especially oily fish such as salmon and canned tuna, are excellent sources of unsaturated fat. Eating unsaturated fat in place of refined grains and sugar can improve blood cholesterol profiles and lower triglycerides, and in turn, lower the risk of heart disease.

It is essential to include a special kind of unsaturated fat, called omega-3 fats, in the diet; good sources include fish, walnuts, flax seeds, and canola oil. Keep in mind that omega-3 fats from marine sources, such as fish and shellfish, have much more powerful health benefits than omega-3 fats from plant sources, like walnuts and flax seeds. But omega-3 fats from plant sources still are a good choice, especially for people who don’t eat fish.

Source: Harvard School of Public Health: www.hsph.harvard.edu/nutritionsource/healthy-fats/