DIET
June 30, 2015

Don't Blame Fat

Four decades of nutrition wisdom may be overturned when the 2015 Dietary Guidelines for Americans are released later this year.

Fat has been maligned since the first Dietary Guidelines were issued in 1980 and for some good reasons. But the pendulum has now swung in the other direction; and when the 2015 Dietary Guidelines for Americans are released later this year, four decades of nutrition guidance may be overturned.

It’s time to change the status quo and embrace what has been learned from years of accumulated research.

The strict limits on dietary fat could be lifted if the government agencies responsible for writing the guidelines follow the recommendations of the Dietary Guidelines Advisory Committee (DGAC). And they should, according to a Viewpoint published in the Journal of the American Medical Association.

Fat Guidelines Have Evolved

Back in 1980 one of the guidelines read, “Avoid too much saturated fat and cholesterol.” Based on available research at the time, it was believed that these nutrients increased the risk of cardiovascular disease by raising the level of LDL (bad) cholesterol in the body.

By 1985 the guidelines were expanded to incorporate all fat, “Avoid too much fat, saturated fat, and cholesterol.” Nutrition textbooks taught that the single most important change we needed to make in our diets was to reduce our fat intake.

Limiting fat or replacing it with carbohydrates does not lower the risk of cardiovascular disease. The new guidelines also don't mention fat restriction as a way to prevent obesity.

Food manufacturers got the message and took the saturated fat out of foods and replaced it with trans fats, which turned out to be a disaster. Putting less fat in foods meant they didn’t taste as good so sugar was added. Low-fat and fat-free foods, made with trans fat, refined grains, and added sugar, took up whole sections of grocery stores in the 1980s and 90s.

In 1995 the guidelines encouraged people to, “Choose a diet that is low in saturated fat and cholesterol and moderate in total fat.” The message continued into the new century with the 2005 guidelines advising, “Keep total fat intake between 20 to 35 percent of calories,” but also calling for a decrease in the consumption of refined grains and added sugars, as scientific evidence began to mount showing that these brought their own health problems.

Fat Free, But Still Overweight

Our obsession with fat-free foods continued into the new century, but began to die down as consumers realized they weren’t losing weight eating fat-free foods. The emphasis in the dietary guidelines shifted in 2010 to replacing calories from saturated and solid fat with those from unsaturated fats, while still consuming less than 35 percent of calories from fat.

Indeed, fat consumption decreased, but the more of these “healthy” fat-free foods we ate, the fatter and sicker — with diabetes and high blood pressure among other obesity-related health problems — we became.

Now all those fat-free foods made with refined grains and added sugars appear to be the real culprits in chronic disease, which brings us to the development of the 2015 Dietary Guidelines for Americans and the opinion expressed in the JAMA Viewpoint.

Scientific evidence now shows that there is little relationship between how much cholesterol we eat and our blood cholesterol levels.

The biggest change in the 2015 DGAC report is that there is no upper limit on fat intake. There is no mention of it as a nutrient of concern, and there are no restrictions on how much we should eat. The report concludes that limiting fat intake, or replacing it with carbohydrates, does not lower the risk of cardiovascular disease. Fat restriction is also not mentioned for the prevention of obesity.

Cholesterol in Food Is Not The Problem

Another change, if instituted, will be removing dietary cholesterol as a nutrient of concern. Scientific evidence now shows that there is little relationship between how much cholesterol we eat and our blood cholesterol levels.

The DGAC report recommends that the new dietary guidelines put more emphasis on increasing the intake of fruits and vegetables, whole grains and legumes, seafood, and dairy products, while decreasing the amount of meats, sugar-sweetened foods and beverages, and refined grains we consume.

According to Dr. Dariush Mozaffarian, co-author of the Viewpoint, “Placing limits on total fat intake has no basis in science and leads to all sorts of wrong industry and consumer decisions. Modern evidence clearly shows that eating more foods rich in healthful fats like nuts, vegetable oils, and fish have protective effects, particularly for cardiovascular disease. Other fat-rich foods, like whole milk and cheese, appear pretty neutral; while many low-fat foods, like low-fat deli meats, fat-free salad dressing, and baked potato chips, are no better and often even worse than full-fat alternatives. It's the food that matters, not its fat content.”

News like this can be confusing to consumers, making them wary of any dietary recommendations, especially after hearing the same low-fat, no-fat message for 40 years. But nutrition is a science, and all sciences advance over time.

In 2015 the Dietary Guidelines Advisory Committee believes the emphasis should be placed on the quality of fats we eat, not the amount. While the jury is still out on saturated fat and its impact on health, the effect is probably neutral because it increases both good and bad cholesterol, said Mozaffarian.

Unsaturated fats like the types found in vegetable oils, fatty fish, avocados, and nuts are good for heart health. The 2015 DGAC report recognizes that healthy fats reduce the risk of cardiovascular disease, even if you exceed the current 35 percent limit. The report also discourages the intake of large amounts of refined grains and added sugars due to the growing body of research that these lead to metabolic problems, cardiovascular disease, and obesity.

News like this can be confusing to consumers, making them wary of any dietary recommendations, especially after hearing the same low-fat, no-fat message for 40 years. Nutrition is a science, and all sciences advance over time as more research is done and more information is gained.

Mozaffarian, a cardiologist and epidemiologist at the Friedman School of Nutrition Science and Policy at Tufts University and his co-author, David S. Ludwig, of Boston Children's Hospital, believe it’s time to change the status quo and embrace what has been learned from years of accumulated research.

“With obesity and chronic disease impacting public health so deeply, we can't miss this critical opportunity to improve the food supply. The USDA and HHS must use the 2015 guidelines to send the message that limiting total fat provides no benefits and actually leads to confusion and bad dietary choices.”

We’ll have to wait and see if the US Department of Agriculture and the Department of Health and Human Services will take the DGAC’s recommendations and remove the fat restriction from the 2015 guidelines. They are scheduled to be released later this year.

In light of the amassed research, removing the stigma from fat and promoting and encouraging a healthy diet pattern based on foods rather than nutrients, even if the foods are high in fat, should help us make better, more informed, food choices and perhaps pave the way for a healthier society.

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