Carbohydrates: Separating fact from fiction.

The role of carbohydrate in a healthy diet has been controversial. The confusion over carbohydrate has come from the long standing limitation of dietary recall studies as well as inability in many of these studies to delineate between the different types of carbohydrates. It is the aim of this paper, to understand and review the data on the role of carbohydrate as pertaining to weight, insulin resistance, diabetes, inflammation, lipids, as well as epidemiological data on long-term cardiovascular outcome and all-cause mortality. We have reviewed the latest epidemiological and intervention studies on fiber, whole grain, and refined carbohydrates on weight, diabetes, lipids as well as major adverse cardiac events that we deemed were scientifically rigorous. High intakes of dietary fiber and whole grains are associated with positive effects on metabolic health while diet high in sugar and refined carbohydrates have negative effects on cardiometabolic health. Consistent evidence indicates that low fat and low carbohydrate diets at comparable energy levels have similar effects on body weight. Large epidemiological studies show when carbohydrates are substituted for animal-derived fat or protein mortality increased while carbohydrate exchanged with plant based protein was associated with mortality reduction. Types of carbohydrate appear to be critical for mortality and cardiovascular events. Evidence shows that quality of the carbohydrate determine cardiometabolic health and cardiovascular events. Given that most people worldwide currently consume less than 20 g of dietary fiber per day with persistently high consumption of refined carbohydrates, current evidence emphasize the need for additional measures to increase the amount and the diversity of fiber intake for improvement of cardiometabolic and cardiovascular outcomes.