Nutrition is a quickly evolving field, and like most sciences, has changed a lot over the last few decades. For instance, do you ever wonder how the low-fat/no-fat diet craze of the 80’s and early 90’s started? Do you wonder how it came to be that Americans were gobbling down entire packages of Snackwell cookies in the name of a low-fat diet, while still eating more calories than ever before and gaining more weight collectively than any previous generation?
It started back in the 1950s with the revolutionary work of a scientist named Dr. Ancel Keys. Keys was a pioneer in the field of cardiovascular disease epidemiology, a.k.a. the study of factors that contribute to heart disease. Keys was interested in dietary patterns, particularly fat intake, as they related to rates of cardiovascular disease. He authored a major groundbreaking study, known as the Seven Countries Study, which looked at the relationship between fat intake and cardiovascular rates in several countries of Europe, as well as Japan and the U.S. He discovered a nearly perfect correlation between the amount of saturated fat intake and risk of heart disease. The more saturated fat in the diet, the higher the risk of heart disease. Tah-dah! Our fear of fat was born.
Controversy exists however, regarding Keys’ work. Critics claim Keys cherry-picked the countries that he included in the study, in order to strengthen the correlation, and left some 15-20 countries out of his study that didn’t support the saturated fat/heart disease relationship. Others contend that these rumors are unfounded; that the correlation still exists regardless of the countries included and that Keys had reasons for discluding countries, unrelated to the statistical data.
Regardless, the effect of Keys’ work on popular opinion was huge and long-lasting. Despite Keys being a proponent of the Mediterranean diet, a diet that is high in unsaturated plant-based fats, somewhere in the early 1980’s, the “avoid saturated fat” message was taken a step further, and all dietary fats were maligned. This caused Americans to shun regular salad dressing, celebrate fat-free ice cream, and purchase “low-fat” products that were heavy in refined carbohydrates, all in an effort to avoid saturated fat.
Research following Dr. Keys’ work confirmed that saturated fats do raise the level of bad cholesterol (LDL) in the blood, and bad cholesterol is a strong risk factor for heart disease, but it’s not quite as simple as once believed. Other factors, such as inflammation in the body, sugar intake, hormones, and other dietary compounds, may play a much bigger role than previously thought. It also matters what you’re replacing saturated fat with in your diet. If you’re substituting refined carbohydrates for saturated fats, you’re probably doing your health no favors. Instead, replacing saturated fats with unsaturated fats, like those found in olives, nuts, avocados, and fish, has shown to reduce risk of heart disease and improve other health indicators. Thankfully, today foods like these are more commonly called “healthy fats”, helping combat the notion that all dietary fat is evil.
To hear more about the subject, tune in to tomorrow’s webinar “All About Carbs, Fats, and Protein” at 12:05pm. It’s now 2015, and while the waters may still be muddy, we’re beginning to get a more clear understanding of how fat, as well as carbohydrates and protein, fit into an optimal diet. I’ll be covering the basics of each macronutrient, as well as discussing our current understanding of the ideal ratio of carbohydrates/fats/protein in the diet. Click here to register!