“Eat Butter.” This was the title of a controversial TIME magazine article in 2014. It suggested that saturated fats are not as harmful to cardiovascular health as was commonly believed for the past few decades. Since the 1970s, studies have shown that consuming large amounts of saturated fats can lead to poor cardiovascular health and heart disease. While this has caused people to pay attention to the amount of saturated fat in their diet, it led to the generalization that consumption of all fats leads to poor cardiovascular health — which caused people to increase their consumption of carbohydrates. The consumption of saturated fats is still controversial, but in recent years studies have begun to tease apart the types of healthy and unhealthy fats, and have shown that the increase in consumption of certain carbohydrates can also be unhealthy.
In our body there are two types of cholesterol — high-density lipoprotein (HDL) is “good cholesterol,” while low-density lipoprotein (LDL) is “bad cholesterol.” Bad cholesterol is a concern because it can clog our arteries, the blood vessels that transport blood from the heart to other parts of the body. When our arteries are clogged, it causes the heart to have to work harder to pump blood to the rest of the body and provide it with the oxygen and nutrients it needs to function properly. If the heart has to work too hard, cardiovascular damage and heart disease may result.
Trans fat has been a major health concern and had to be removed from foods because it increases LDL while also decreasing HDL, negatively impacting the levels of both types of cholesterol. However, saturated fats, such as those found in red meat and dairy, only elevate LDL levels. While this may still be harmful, the effect of saturated fat on LDL seems to be even more nuanced. LDL itself is composed of two different types of particles: small, dense particles, which have been shown to lead to heart disease, and large, fluffy particles, which appear to have no negative effect on heart health. Saturated fat seems to increase the level of large, fluffy LDL particles and therefore may not be as unhealthy as the prevailing ideology suggests.
Unsaturated fats, on the other hand, are beneficial; these are the fats found in vegetables, nuts, and fish. In general, our bodies need some fat as a source of energy and to help repair certain components of our cells. Therefore, the consumption of unsaturated fats is recommended over saturated fats. In fact, the idea behind the consumption of unsaturated fats arose from studies of the Mediterranean diet. Research showed that people in the Mediterranean region, despite having diets high in fat, nevertheless have a low rate of heart disease because the fats they consume are largely unsaturated.
Along with the decreased consumption of saturated fats over the past few decades came an increased consumption of carbohydrates. Most carbohydrates are eventually broken down within the body to glucose, a basic sugar unit. However, scientists have begun to categorize different carbs based on how quickly they are broken down into glucose, and therefore how quickly they increase sugar levels within the body. Refined carbs, like white bread, rice, and potatoes, have a high glycemic index — that is, they are quickly broken down into glucose and thus elevate free sugar levels within the body. Foods that have a low glycemic index are items such as carrots, grapefruit, peanuts, and hummus, which don’t greatly affect glucose levels within the body. Carbohydrates that have a high glycemic index should be consumed in smaller quantities because the constant and rapid increase in glucose levels within the body can eventually lead to problems such as insulin resistance (a sign of type 2 diabetes) and fatty liver disease. These two diseases can in turn damage cardiovascular health.
While the intricacies of the various fats and carbohydrates we consume continue to be studied, one idea seems to remain the same: everything should be consumed in moderation. Nonetheless, understanding the impact of various foods on our body is beneficial for leading a healthy life and taking care of a valuable organ, the heart.