Carbohydrates are the main source of glucose in the blood, which is the most important fuel for all cells in the body.

In recent decades, so-called “low-carb” diets have become popular. These diets propose consuming almost exclusively foods high in protein and polyunsaturated fats, especially those of animal origin, such as meat and dairy products, but restricting carbohydrate intake as much as possible.


The authors of these “diets” have made serious accusations against carbohydrates: that they are to blame for our weight gain.


On the other hand, the WHO (World Health Organization) recommends an intake of 55-75% of our total energy from carbohydrates (WHO/FAO 2003), which is in line with the famous “nutrition pyramid” that we have been taught for generations in elementary and high school.

Who is right, or are they both wrong?

Let’s start with the basic theory: Carbohydrates are the main source of glucose in the blood, which is the most important fuel for all cells in the body and the only source of energy for the brain and red blood cells (erythrocytes). (Balch, 2007)

There are mainly two types of carbohydrates:

– Simple carbohydrates, (or sugars), and

– Complex carbohydrates

Complex carbohydrates consist of saccharide molecules that form longer chains. Complex carbohydrates include fiber and starches. Foods that are rich in complex carbohydrates are vegetables, whole grains (not processed), peas, and beans.

However, it is a big mistake to equate a food with a nutrient.

For example, when analyzing the calories provided by broccoli, about 50% come from protein, 25% from carbohydrates, and 25% from fat.

In the case of beef (steak) only 35% comes from protein, and 60% from polyunsaturated fats (the cause of heart attacks and hypertension).

We cannot label natural foods as:

  • meat = protein
  • potato = carbohydrates
  • avocado = fat

Because in addition to the three basic macro-nutrients, each food has a myriad of nutrients, especially plant foods: minerals, antioxidants, phytochemicals, vitamins, fatty acids, fibre, enzymes, etc.

Our digestive system works very well with complex carbohydrates when they are consumed in their natural state (vegetables, fruits, grains), it breaks down the molecules at their normal rate, glucose and insulin levels behave within their normal range.

But the human being, has wanted to “compose” natural foods and has processed them artificially. The result of this is “refined simple carbohydrates”.

Many of the foods that we consume daily, the vast majority of the population, contain this type of refined carbohydrates. We’ll give you a short list: white tortilla, white bread, pasta, noodle soup, candy, cupcakes, yogurt, ice cream, jam, chocolate, cookies, and boxed breakfast cereals (there are still many more to mention).

The problem with these refined carbohydrates is that their absorption is very fast, lacking fiber and other nutrients, our body takes only the energy (calories), and our blood glucose and insulin level is decompensated and these level mismatches (sudden spikes) send a signal of body fat accumulation to our body (Furhman, 2003).

The WHO and the food pyramid have failed because they recommend eating carbohydrates without distinguishing between refined and complex carbohydrates.

Low-carb diets (such as the famous Atkins diet) have failed because they have generalized the negative effect of eating refined carbohydrates, and also prohibit natural complex carbohydrates such as fruits and vegetables which are vitally important to our nutrition.


There are certain types of carbohydrates that make us put on weight: refined (or isolated) carbohydrates, such as sugar, white flour, pasta, and pastries.

But there are also carbohydrates that make us lose weight: the complex carbohydrates contained in vegetables, legumes, fruits, cereals and seeds.

Although fruits contain simple carbohydrates (fructose), they are not harmful since they come in their protective package of fiber, vitamins, phytochemicals and antioxidants.