What are
Under the term "starchy" different foods and food products are grouped together with the generous presence of starch, the reserve carbohydrate typical of the plant world.
The plants accumulate starch as an energy reserve to face the winter (that's why tubers like the potato are particularly rich) or to allow seed germination and the subsequent development of the seedling.
What are they?
Diet
Nutritional role of starchy foods
If in plants starch is necessary to ensure its survival during the winter, and to allow seed germination, in humans it has represented - from the discovery of agriculture onwards - the predominant energy nutrient. Once ingested, through saliva, chewing and intestinal enzymes, starch is broken down, ring by ring, into the individual sugars that constitute it, or into individual glucose units that - intertwined through linear and branched bonds - damage starch origin. TO
intestinal level, the glucose deriving from starch is absorbed and released into the bloodstream, then used by the cells for the relevant metabolic processes, or stored as a short-term energy reserve (glycogen deposits in the muscles and liver) or in the long term (conversion into triglycerides at hepatic and adipose level).
Excess and Health
It follows that excessive consumption of starchy foods over time, especially in the absence of regular and demanding physical activity, is responsible for overweight, obesity and metabolic diseases such as insulin resistance → diabetes. Hence the advice, too often extreme, to reduce the consumption of starchy foods in one's diet when one wants to lose weight.
Too many starchy foods, especially if cooked for a long time, refined or processed on an industrial level, have negative actions on the levels of glucose in the blood, which rise excessively following their ingestion; this effect, in addition to being potentially responsible - in the long term - for the onset of diabetes, tends to determine a state of well-being, contentment and numbness due to the condition of hyperglycemia and the stimulus on the release of serotonin. Nevertheless, the condition of hyperglycaemia is followed by an important secretion of insulin which tends to bring back glucose levels to normal; this biological event causes a negative rebound in glycemic levels (the so-called postprandial reactive hypoglycemia), which stimulates the hypothalamic center of hunger. Thus we enter a sort of vicious circle that - especially in already overweight and sedentary individuals - leads to the new ingestion of refined starchy foods (see below) and to the inevitable weight gain, with all the negative consequences of the case.
Whole Starchy Foods
It is good to remember that natural starchy sources do not only contain starch, but also the other nutrients necessary for the plant and for seed germination: proteins, vitamins, mineral salts, unsaturated fats, and fibers. Most of these nutrients are lost in the refining processes, which are intended to improve the palatability, digestibility and storage of starchy foods. Following this practice, however, products rich in "empty" calories are obtained, because they are too rich in energy and poor in essential nutrients, such as vitamins and mineral salts.
Hence the fashion, in some respects acceptable, of preferring whole foods, richer in nutritive principles and more satiating.
Food tips
Ultimately, starchy foods must remain the pillars of human nutrition, not only because of the nutritional aspects so dear to classic school nutritionists, but also for reasons of environmental sustainability. If we consider the ever more widespread eating habits "hit and run", it is very necessary - to reduce the incidence of so-called "wellness diseases" (obesity, diabetes, etc.) - to moderate first the quantities of starchy foods, to give more space to fresh vegetables and lean proteins, and prefer, at least in a daily meal, whole foods to refined ones.
The "modern" Mediterranean diet fails because in its original concept, typical of the post-war period, it was inserted in a context of caloric poverty and regular physical activity; today the Mediterranean diet, which is based on the prevalent consumption of starchy foods, but also of fish, lean proteins and vegetable oils, is so criticized because it is inserted in a context of hyper-feeding (too many calories!) in which one feeds oneself by snack and various cereals, exaggerating with the quantities and preferring the latter to fruit, fresh vegetables, lean proteins and "good fats", such as those of fish or olive oil.
Last but not least, a sedentary lifestyle further aggravates the problem: just think that the diet recommended for marathon runners, notoriously rather thin and thin, involves a much more consistent and preponderant supply of starchy foods than the rest of the population.
