Carbohydrates are a fundamental macronutrient, serving as the body’s primary energy source. They are found in a wide array of foods and drinks.
What Carbohydrates Are
Carbohydrates are broadly categorized into simple and complex types, differing in their chemical structure and how the body processes them. Simple carbohydrates, or sugars, have a basic chemical structure and are easily digested. Examples include glucose and fructose, found naturally in fruits, vegetables, and milk, as well as added sugars in processed foods like candy and sodas.
Complex carbohydrates, such as starches and fiber, are made of longer chains of sugar molecules and take more time for the body to break down. Starches are found in grains like bread, cereal, and pasta, and in vegetables such as potatoes, peas, and corn. Fiber, a complex carbohydrate, is not easily broken down and is found in fruits, vegetables, nuts, seeds, beans, and whole grains.
How the Body Uses Carbohydrates
The body begins breaking down carbohydrates in the mouth, where enzymes start to work on starches. This process continues as food travels through the digestive system, eventually breaking down carbohydrates into glucose, a simple sugar. Glucose is then absorbed into the bloodstream from the small intestine.
Once in the bloodstream, glucose becomes the main source of energy for the body’s cells, tissues, and organs. The hormone insulin, produced by the pancreas, helps glucose enter cells for immediate energy. If there is more glucose than the body needs right away, insulin also helps store the excess as glycogen in the liver and muscles for later use. The liver can store approximately 100g of glycogen, while muscles can hold about 400-500g. When these glycogen reserves are full, any remaining excess glucose can be converted into fat for long-term storage.
Impacts of High Carbohydrate Intake
A diet with adequate carbohydrate intake provides sustained energy for daily activities and brain function. Complex carbohydrates, in particular, offer a steady release of glucose into the bloodstream due to their slower digestion, which supports consistent energy levels and can be beneficial for athletic performance. These types of carbohydrates, rich in fiber, also contribute to a feeling of fullness, aiding in managing overall food intake.
However, the impact of a high carbohydrate intake varies significantly depending on the type of carbohydrates consumed. When a high intake comes from refined or simple carbohydrates, such as those found in sugary drinks, white bread, and many processed foods, it can lead to rapid blood sugar spikes. These quick increases in blood sugar can trigger a surge of insulin, which may result in a subsequent drop in blood sugar, potentially leading to increased hunger and cravings. Over time, frequent consumption of refined carbohydrates has been associated with an increased risk of weight gain, especially around the abdomen, if energy intake consistently exceeds expenditure. High intake of refined carbohydrates has also been linked to an increased risk of developing type 2 diabetes, heart disease, and metabolic syndrome, a cluster of conditions including high blood pressure and abnormal cholesterol levels.
Making Informed Carbohydrate Choices
Making informed choices about carbohydrates involves prioritizing whole, unprocessed sources over refined ones. Opting for whole grains like brown rice, whole-wheat bread, and oats is beneficial because they retain their natural fiber, vitamins, and minerals. These whole carbohydrates are digested more slowly, leading to a more gradual rise in blood sugar levels compared to refined grains, which have had much of their fiber and nutrients removed during processing.
Incorporating fiber-rich carbohydrates from fruits, vegetables, and legumes is also recommended. Fiber supports digestive health, helps manage blood sugar, and can contribute to a feeling of fullness, reducing overeating. Limiting foods with added sugars and refined grains, such as candy, sugary beverages, and many baked goods, can help improve overall dietary quality and health outcomes.