Carbohydrates (also known as sugars or glucides) are one of the macronutrients that provide energy; they are found in both cells and the blood.
Carbohydrates supply about 4 calories (kcal) per gram and are present in foods of both plant and animal origin; in the Mediterranean diet, carbohydrates normally come from grains (bread, pasta, etc.) and fruits.

Carbohydrates are an essential part of one's daily diet, the amount needed varying according to age, sex, body weight and physical activity. The amount of sugar (in particular glucose) in the blood (called glycemia and/or blood sugar level) must be kept constant because, when the amount of sugar exceeds what the body needs, we end up with very high blood sugar levels (hyperglycemia), one of the main symptoms of diabetes and a situation that leads to weight gain and obesity.

Complex Carbohydrates and Simple Sugars

While they are synonymous, the words sugars and carbohydrates are often given different meanings: the term carbohydrates is generally used to indicate complex sugars while the term sugars is used for simple sugars. This distinction is also used by European food labeling regulations. The difference between complex and simple sugars depends on the number of molecules in the compound and this determines how they are metabolized.

Complex Sugars

The key feature of complex sugars is slow digestion: they are assimilated more slowly than simple sugars and thus the energy is released gradually, leaving us feeling sated longer. Many foods contain complex sugars (polysaccharides) but, first and foremost, they are found in starchy foods (cereals): pasta, bread, rice, legumes, potatoes, chestnuts, and bananas, as well as in some herbaceous species such as buckwheat, quinoa, etc.

In the human body, complex sugars are accumulated in the muscles and liver as glycogen, a "reservoir" used to maintain blood glycemia levels when the amounts of sugar in circulation are inadequate.

Simple Sugars

These are defined as “instant-energy sugars" because the body absorbs them more quickly for an immediate energy boost. These are carbohydrates derived from different foods having a different number of molecules. Simple sugars (monosaccharides) include fructose and glucose, sucrose (better known as common sugar) and lactose (disaccharides). Fructose is also the "sugar" found in honey, in various syrups such as maple syrup, and in most fruit-based preparations: juices, compotes, etc.. Extracted from sugar beets or sugar cane, sucrose is the sugar most commonly added to prepared foods and beverages: cookies, baked goods, jams. When eaten alone, simple sugars quickly raise the blood sugar level, giving an instant energy boost (after all it is the “instant-energy” sugar). This, however, is promptly followed by a drop in blood sugar which causes a feeling of hunger.

Main functions

Source of energy - They are the simplest source the body can draw on to stay alive: to sleep, breathe, move, think.

Energy reserve - Sugars not consumed by basal metabolism and daily physical and intellectual activities are often stored as energy reserves (glycogen) or transformed into fat, thus building up fat tissue as another pool of energy.

Daily requirement

Sugars should account for most of the energy we derive from macronutrients (sugars, proteins and fats) — around 50-60% of one’s daily energy requirement. In a well-balanced diet, on average, 10-15% of the carbohydrates should come from simple sugars. In practice, if a person’s daily requirement is 2,000 kcal, around 1000-1200 of these calories should come from carbohydrates and, of these, simple sugars should account for 200-300 kcal.

Example of the contribution from sugars

One hectogram (100 grams) of raw pasta has about 70 g of complex sugars accounting for 280 Kcal.

A 100 gram roll has approximately 48 g of complex sugars and thus approximately 192 Kcal.

Unpeeled apple, again 100 grams worth, has approximately 14 g of simple sugars and thus 56 Kcal. Instead, 100 g of fresh figs has 12 g of simple sugars and thus 48 Kcal, while the same amount of dried figs has 58 g for 232 kcal.

A small fruit juice (125 ml), containing both the fructose from the fruit itself and added sucrose, provides about 15 grams of sugar and thus 60 Kcal.

A medium-sized sweetened cola (200 ml) has around 21 g of simple sugars for 84 Kcal.


Many believe that there are substantial differences between the simple and complex sugars in various foods. However, all sugars or carbohydrates actually have the same nutritional value, no matter what their color or what they were derived from. The nutritional characteristics of brown sugar and white sugar are almost exactly the same; what differs, instead, is the flavor and color due to the molasses present which, in turn, depend on how refined the product is. The honey and many other preparations derived from fruits or plant lymph bring other substances above and beyond the sugar, and yet this does not change the nutritional properties of the sugar which always comes in one of two forms: simple or complex. In whole wheat or white pasta, quantity being equal, the starch (complex sugars) has the same nutritional value, the difference lies in the increased amount of fiber since the flour in whole wheat pasta is less refined. Fructose has a greater sweetening capacity than other types of sugar. Chemical sweeteners are not sugar and do not provide calories; they only change the perceived flavor of the food they are added to.

So what about tomatoes?

The slightly sweet taste of a ripe tomato is derived from approximately 3.5% grams of fructose — the macronutrient for this vegetable which accounts for nearly all the energy. 100 g of tomato has around 20 kcal, 14 of which come from sugars.

That is an insignificant amount if we consider the other virtues of this wonderful plant — vitamins, minerals and antioxidants.

Minerals, among all the nutrients, are inorganic substances present in nature and in plant and animal food.
They are not always in the form of salt. Minerals are considered essential not only because life cannot be sustained without them, but because our body is unable to synthesize them. Man is forced to eat them with food adopting a varied diet to ensure an adequate intake of the necessary minerals.

Minerals are classified according to the quantity required by the body: Macroelements, Microelements, and Trace elements.

Macroelements: Calcium, Phosphorus, Magnesium, Sodium, Potassium and Chloride, the requirement is more than 100 mg/day.

Microelements: Iron, Copper, Zinc, Fluoride, Iodine, Selenium, Chrome and Cobalt, the requirement is from 1 to 100 mg/day.

Trace elements: Bromine, Chrome, Nickel, Lithium, Silicon, Tin and others.
There are only traces of these in the body and the requirement is below 1 mg/day.

Function of minerals

Minerals are present in all food chains; plants absorb them from the soil and from fertilizers, including animal kind ones.
They pass from the plant to the animal world in a continuous cycle. Minerals make up 6% of body weight, are an essential part of our cells and with other substances they form bones and tissues. Minerals are also part of the metabolic system so they are eaten with fats, proteins and sugars, are essential to synthesize proteins, to keep body temperature and blood pressure stable as well as to supply  the cardiovascular system and perform many other vital functions. They are constantly eliminated with urine, feces and sweat so they must be reintegrated daily. Among the many minerals and numerous functions, below we take a close look at the properties of the most important minerals for human beings.

It is the most abundant mineral present in the human body, which contains between 1 and 1.5 kg of calcium.
The majority of bones and teeth are made of calcium, but the mineral also intervenes in other important functions such as the nervous system and cardio-circulatory system. Calcium deficiency can prevent a correct physiological growth in children and cause osteoporosis at an advanced age.

It is a very important micro-nutrient for health because it carries out many functions inside the human body. It is an element of the red blood cells, part of numerous proteins including hemoglobin, myoglobin and cytochromes which are essential for transporting and  using oxygen. A shortage of this mineral causes iron-deficiency anemia. Iron deficiency in the blood can be higher in women during childbearing age, pregnancy and breastfeeding.

It works in synergy with calcium and vitamin D forming the material that makes bones.

It is above all an essential part of hormones produced by the thyroid. Iodine deficiency causes goiter and, in pregnant women, can lead to a mentally retarded child.

It intervenes in muscle function, facilitating the contraction of the muscles including the heart.

It is above all important for the proper function and health condition of the nervous and muscle systems, including the heart.

It intervenes in the hydro-saline balance, avoiding excessive water loss.

It is a powerful antioxidant and, like zinc, it reduces the damage caused by excess free radicals.
It has a synergistic effect with vitamin E.

It is a powerful antioxidant; it intervenes in growth, in prostate function, works on the immune system and in healing wounds.
It also intervenes in protein synthesis and in collagen formation.

About tomatoes

Tomatoes contribute a large quantity of potassium (approx. 650 mg per 100g of product).
This mineral is part of the plasmatic electrolytes, the minerals which work on blood pressure, muscle strength, and reflexes. Potassium deficiency can cause fainting and muscle cramps. For these reasons tomatoes are an important food in the diet of athletes.

The contents of this article are in accordance with the parameters set out by the European Food Safety Authority - EFSA.