Along with proteins and fats, carbohydrates are one of the essential nutrients we need to nourish ourselves properly. They are also the main source of energy for the body, particularly for the brain and muscles, which largely depends on glucose, especially during physical activity.
But not all carbohydrates are the same or serve the same purpose. Therefore, it is important to know their types and functions to know how to choose. And for that we have Alejandro Martínez Rodríguez, dietician-nutritionist, professor of the Department of Analytical Chemistry, Nutrition and Bromatology and director of the European Institute of Exercise and Health at the University of Alicante.
What are carbohydrates?
From a chemical point of view, they are composed of carbon, hydrogen and oxygen that respond to the general formula Cn(H₂O)n. Hence its name carbohydrates. They are essential for their energy contribution (4 kcal per gram), but they are also essential from a nutritional point of view.
«Carbohydrates determine sensory characteristics of foods such as texture, color and the ability to retain water. In addition, they participate in chemical reactions during processing, such as caramelization or the Maillard reaction, responsible for the characteristic aroma and flavor of many cooked foods,» says the expert.
Types of carbohydrates
The distinction between carbohydrates is based on their chemical structure and the speed with which they are digested and absorbed. They are classified into simple and complex carbohydrates.
Simple carbohydrates
According to the expert, “they are also often called sugars and are short-chain carbohydrates that break down quickly.” They are found naturally in foods such as fruits and milk (fructose and lactose, respectively), and honey and table sugar. They are also found in the form of added sugars in processed products such as soft drinks, sweets and pastries.
Complex carbohydrates
“They are longer chains of sugars that make up starches, for example, and fiber and require more time to be digested, which provides a slower and more sustained release of energy.” They are found in foods such as whole grains and their derivatives (pan, pasta, rice, etc.), legumes, tubers and some vegetables.
Are there good and bad carbohydrates?
Martínez Rodríguez is categorical in answering this question: “Current science advises against classifying foods as good oh bad”. And he chooses to use the name high or low quality carbohydrates. Once this is taken into account, the expert points out:
Food sources of high-quality carbohydrates.: those that come from natural and minimally processed sources. They are rich in fiber, vitamins, minerals and beneficial phytochemicals. We are talking about whole grains, legumes, whole fruits and vegetables, nuts, among others. Its consumption is associated with a lower risk of chronic diseases.
Food sources of low-quality carbohydrates.: Found in processed and refined foods. They tend to be low in fiber and nutrients. We are talking about pastries, sweets and foods made with refined non-whole flour, and sugary drinks, which also usually contain poor quality fats. Its excessive consumption is related to a higher risk of obesity, type 2 diabetes and cardiovascular diseases.
Function of carbohydrates in the body.
Carbohydrates perform several vital functions:
- Energy source: “They provide the energy necessary for all bodily functions, from physical activity to thinking,” says the expert.
- Muscle protection: Carbohydrates prevent the use of protein as an energy source. That is, when carbohydrate intake is insufficient, the body uses muscle to maintain blood glucose, “which can compromise the synthesis and maintenance of muscle mass, especially in situations of intense exercise or caloric restriction.”
- Digestive health: Fiber (a set of indigestible carbohydrates) is essential for the proper functioning of the intestine, preventing constipation and feeding the beneficial intestinal microbiota. All of this favors the production of short-chain fatty acids and modulates the composition of said microbiota. Beneficial effects on immune and metabolic function are thus obtained.
Foods rich in carbohydrates (and healthy)
The key, in the words of the nutritionist dietitian, is “choosing sources of carbohydrates that also provide other essential nutrients.” And he gives some examples.
whole grains
Whole grain rice, bread or pasta, as well as whole grains such as oats, among others, are an excellent source of complex carbohydrates, vitamins, minerals, phytochemicals and fiber. Fiber slows down digestion, helping to control blood sugar levels and prolonging the feeling of satiety.
legumes
Foods such as lentils, chickpeas and beans are an exceptional source of slowly digestible carbohydrates, as well as being rich in protein, micronutrients and fiber.
fruits and vegetables
They are a source of simple carbohydrates or sugars of natural origin (mainly fructose), but they are accompanied by a large amount of fiber, vitamins, minerals and antioxidants. Apples, bananas, pomegranates, cabbage or spinach are perfect examples, among the wide diversity of seasonal and locally produced fruits and vegetables.
tubers
Foods such as potatoes, sweet potatoes or cassava can be part of a healthy diet. They are sources of starch, micronutrients and fiber. Cooking and chilling them can even increase their resistant starch content, which is beneficial for gut health. This also applies to whole grains and their derivatives such as bread or pasta.
Plant foods that provide carbohydrates.
The vast majority of foods rich in carbohydrates, and the most important in our diet, are of plant origin. “In fact, the only significant animal source of carbohydrates is lactose (the natural sugar in milk),” adds the expert.
- Cereals and their derivatives: Wheat, rice, oats, corn, frying pan, pasta, etc.
- Legumes: Lentils, chickpeas, beans, peas.
- Vegetables: all seasons
- Tubers: Potatoes, sweet potatoes, cassava and derivatives
- Fruit: all seasons
“When consumed integrally, these foods provide, in addition to energy, fiber, phytochemicals, vitamins and minerals essential to the body,” he concludes.
Foods with carbohydrates that should be avoided
It is not about eliminating food sources of carbohydrates completely, but rather reducing their usual consumption in favor of healthier options. The nutritionist dietitian refers to:
- Added sugarsfound in sugary drinks, sweets, cookies, industrial pastries and most boxed breakfast cereals.
- Refined flours: Products made with white flour, such as white bread, pasta and most cookies and other pastries. They lack the fiber and nutrients present in their whole grain versions.
Is it convenient to eat foods with carbohydrates at all meals?
Martínez Rodríguez asserts that «it is not strictly necessary to consume carbohydrates at all meals, but a regular distribution of carbohydrates, mainly complex, throughout the day can favor the maintenance of blood glucose and satiety, especially in people with specific metabolic needs such as diabetes treated with insulin, pregnancy, lactation or high physical activity.»
In this sense, the expert insists that the importance of the quality and variety of food sources of carbohydrates are more relevant than the exact quantity or frequency of consumption.
The ALDI Council
Do you have sweet cravings mid-morning? Have on hand a handful of unsalted nuts, an apple, a banana, or whatever fruit you like the most. You will kill the itch without consuming unhealthy sugars.
Alejandro Martinez. Dietitian-nutritionist and member of the Spanish Academy of Nutrition and Dietetics. He is currently a contracted professor in the Department of Analytical Chemistry, Nutrition and Food Science at the University of Alicante. Accredited as a University Professor in the area of Health Sciences by ANECA. Linked to teaching and research, since 2014, at the Universidad Católica San Antonio de Murcia. He has published 84 scientific publications and has presented more than 90 papers at scientific conferences, most of them international. In 2019 he received the award for best research from the Spanish Society of Sports Medicine.
