Before the infamously misleading studies in the 1970s that falsely concluded fat intake caused higher cholesterol levels as well as death by heart disease, Americans were taking in 45 percent of their calories from fats and oils. At that point, the rates of adult obesity and diabetes were 13 percent and under 1 percent, respectively. Now, Americans only take 33 percent of their calories from fats and oils, but obesity rates have increased to 34 percent while diabetes rates have skyrocketed to 11 percent in adults. Since then, instead of the predicted decline in the systemic disorders, the number of individuals suffering from heart disease, diabetes and obesity has more than doubled in the past 20 years. The question is: Why?
These studies ushered in an era that demonized the necessary macronutrient, causing food companies to eliminate fat from many of their products. This generated a new market and a new selling point for companies. They began introducing low-fat and fat-free counterparts of their products and touted them as “heart healthy.” However, as a result, the taste of their products suffered, forcing producers to replace lipids with refined sugars as a means of improving palatability. What was not understood at that time was that the replacement of fat with sugar would remove a nutrient necessary for the synthesis of cell membranes and vital hormones for proper growth and development.
When the country as a whole made the decision to remove fat from the typical American diet, the common misconception arose that an increased fat intake caused obesity and heart disease. However, the studies from the 1970s transformed correlational data to a definitive causality — a flaw pointed out in later studies. Namely, Harvard’s Public Health division led the study that refuted this long-held belief. They asked one group of subjects to replace their saturated fat intake with carbohydrates and another group to replace it with mono- and polyunsaturated fats. The findings indicated that those on the low-fat diet were more prone to developing hyperglycemia whereas their “fatty” counterparts showed an increase in heart health. Furthermore, this study linked the increased refined sugar intake to the increased disease rates of diabetes and obesity and also made a strong case for a reintegration of fats into the American diet. This study was also the first to highlight the fact that the quality of the fats in the American diet needs to be improved. This study illuminated our shaded understanding of fat as a component in our diet and indicated that the main impetus for our dismal walk into an epidemic arose the day we cut out fat and accepted sugar.
In the time of hunters and gatherers, our sugar intake was highly limited but efficiently used. As a result, our bodies developed a storage system that relied on insulin to move sugars into muscles for future use. However, in our current sedentary environment, that fuel source has been underused, causing fat to be stored around organs. Furthermore, the quality of our sugars has fallen significantly, with the liver constantly being bombarded with refined white breads and sugars (both of which are processed in the same manner), which it then stores as body adipose tissue if they are not mobilized through activity. But when storage space is occupied, sugar begins flowing through blood at elevated levels, damaging nerves and muscle on the way and forcing the pancreas into overdrive. To prevent pronounced muscle damage with elevated sugar levels, the body has a natural defense mechanism that releases c-peptide along with insulin to dampen sugar’s negative effects. But, this defense system cannot function properly if the scale of sugar intake is beyond threshold. Sadly, since the brain relies solely on glucose to function, these detriments have generally been overlooked.
In America we have, as a result of removing fat, added a new silent killer into our foods that is the real cause of the increase in prevalence of preventable diseases. The hallmark misconception of the fat-demonizing era serves as a lesson from which we must learn; a new emphasis needs to be placed on the quality of the fats and sugars instead of the macronutrients as a whole. But for now, the refined sugar intake that has skyrocketed tenfold in the past century has taken the crown off of fat as the new point of concern for healthcare professionals.