“Following a low-carb (low carbohydrate content) diet, by definition means increasing fats and/or proteins, but these nutrients cannot play the role of carbohydrates, and when they do, they do it badly. A low-carb diet becomes a high-protein one and the protein in excess loses its natural plasticity to take on an energy-generating function, thus producing “dirty” energy that is not clean because it forces the body to eliminate the nitrogen in excess. It’s like deciding to return to heating our homes with coal instead of methane.”
Luca Piretta, specialist in Gastroenterology and Digestive Endoscopy, as well as Human Nutritional Science in the Department of Clinical Sciences at La Sapienza University, is direct when speaking about the risks we run when we significantly reduce—or even eliminate—the carbohydrates we eat.
Diet? It’s not just about numbers – “Carbohydrates are clean energy. Some tissues, such as the brain and red blood cells, only work with glucose (even if neurons can adapt to ketone bodies) that must be supplied in the right quantity.” And this nutritionist warns: “It’s as if the alchemy of a healthy diet were based exclusively on a purely mathematical calculation: take a bit away here and add it there. It’s as if calories were all the same and represent the only parameter to take into consideration when deciding what kind of diet to choose.
All foods are not the same – Piretta continues: “I can’t substitute apples with fish, pasta with butter or fruit with meat, just maintaining the overall number of calories.” And what about carbohydrates? “To avoid having excessive impact on glycemia and insulin levels, carbohydrates must not be abolished, we have to learn how to consume them. You just have to be aware of the glycemic index which can be worked with, not just through the choice of foods, but also learning how to prepare and combine them. For example, eating pasta ‘al dente’, with a mushroom or asparagus sauce, has a very low impact on post-prandial blood sugar levels.”
The car metaphor – “In other words,” Piretta concludes, “with diet, talking only about calories and low carbs is like going to buy a car and asking only how fast it goes, and forgetting to ask if it is a diesel, if it is 3- or 5-door, if it has 2- or 4-wheel traction, if it is yellow or black and if it has a pleasing design or is just a box on wheels.”