The nutritional quality of the diet

To evaluate the nutritional quality of the diet, we must take into account many elements related to the quantities and qualities of the foods regularly used by an individual to satisfy his or her nutritional needs. However, other nutritional aspects can be evaluated, which have a general influence on the health of all or most of the population.

To judge the quality of the diet in a general way, the following aspects should be evaluated:

• Eating habits.

• The distribution of the energy provided by each of the meals.

• The comparison of the dietary intake with the recommended intakes.

• Determine the energy values and the caloric profile of the diet.

• Assessing the nutrient density of the diet.

The eating habits that a person adopts on a daily basis, depending on his or her food preferences, economic situation and social environment, among other factors, form part of his or her eating pattern.

Here are some eating habits that directly influence the quality of the diet:

• Dietary diversity: those who, for different reasons, exclude certain foods from their diet, may be at risk of developing nutritional deficiencies. For example, a diet low in animal protein can lead to iron deficiency, which could lead to iron deficiency anemia.

• Quantity and distribution of meals: the daily diet should be properly organized throughout the day, with appropriate portions for each moment. For example, dinners should be light and eaten at least two hours before bedtime. Those who eat too much dinner just before bedtime may suffer from digestive problems and obesity.

Eating habits

The eating patterns that the individual follows on a daily basis, depending on food preferences, economic situation and social environment, among other factors, constitute eating habits.

Some eating habits that have a direct impact on the quality of the diet:

• Variety of the diet: people who, for various reasons, do not include certain foods in the diet, run the risk of suffering nutrient deficiencies. For example: diets poor in animal proteins could lack sufficient iron, which would favor the appearance of iron deficiency anemia.

• Number and timing of meals: the diet intended to be consumed during the day should be correctly distributed throughout the day and in appropriate portions at each moment. For example: dinners should be light and at least two hours before going to bed. People who eat very large dinners before going to bed may suffer from gastrointestinal diseases and obesity.

• Quantities of ingredients in meals: in the preparation of meals, we cannot exaggerate the use of a certain element, in order to accentuate a favorite flavor, without taking into account the impact it may have on our health. Example: those who prepare food with high levels of salt are at risk of suffering from cardiovascular diseases.

• Amount of food to eat at each meal: when sitting at the table, we must take into account our needs, we cannot eat a bite and think that it is enough. Nor is it necessary or healthy to get used to eating until we feel full. The imbalances in the quantities, always harm the health, by malnutrition or overweight.

Distribution of the energy provided by each of the meals

It is recommended to have five meals a day, where breakfast contributes 25% of the daily energy, the mid-morning snack 10%, lunch 35%, the snack between lunch and dinner 10% and dinner 20%. The following table shows an example of the distribution of calorie intakes, in the different meals, throughout the day. Maximum calories: 2'290 kilo calories.

Comparison of dietary intakes with recommended intakes (ir)

The comparison of the dietary intake with the reference values of the recommended intakes allows an estimate to be made in order to evaluate the adequacy of the diet for an individual or population group. This method does not allow the determination of nutritional deficiencies in specific individuals, for which biochemical assessments would be necessary.

When planning and evaluating diets based on the recommended intakes of vitamins and minerals, it should be taken into account that the reference values present in these diets are slightly higher than what people really need.

The following table shows the comparison between the energy, protein and vitamin intake of a diet for 9-year-old children and the recommended intake values (ir) for that age. Note that the data in red identifies the nutrients that are lower than the recommended amounts.

Energy values and calorie profile of the diet

The energy values of the diet must guarantee the supply of sufficient energy for the body to maintain a stable body mass index between 20 and 25 kilograms per square meter.

The caloric value of the diet can be evaluated by monitoring the individual's weight for a month, if during that stage, the weight remained constant, the energy intakes are adequate. If there was an increase in weight, the diet is providing more energy than necessary; if on the contrary, the weight decreases, the energy provided by the diet is not enough.

For the caloric intake of the diet to be correct, it is not enough that it generally guarantees the energy levels. The diet must also ensure that energy is provided, with adequate levels for each of the macronutrients. The percentages of energy contribution of each macronutrient to the diet are called the caloric profile of the diet.

The recommended caloric profile is as follows:

• Proteins should provide between 10% and 15% of the total calories needed.

• Lipids should provide between 30% and 35% of the total calories needed, if olive oil is used as the main fat.

• Carbohydrates should provide between 50% and 60% of the total calories needed. Slow absorption carbohydrates are recommended, such as whole grains, vegetables, fruits and vegetables.

• If alcohol is consumed, it is recommended that the intake be less than 10% of the total energy required.

• The following table shows an example of the calculation of the caloric profile for a diet of 2002 kilocalories.

Nutrient density of the diet

The density is the amount of nutrients contained in the diet, per 1'000 kilocalories of energy provided. The greater the number of nutrients, the higher the quality of the diet.

The density of nutrients in the diet increases when the variety of foods is increased, generally diets that provide sufficient energy values guarantee an adequate density.

Diets that include simple carbohydrates, such as industrial soft drinks, sweets and saturated fats, such as butter, sausages, or coconut and palm oils, have a low nutrient density, since they can satisfy energy needs, but do not provide proteins, vitamins and minerals in appreciable quantities.

Nutrient density is a parameter that must be controlled, especially when diets are used to reduce weight, since the reduction of food intake, in order to reduce the energy levels provided by the diet, could also reduce the number of nutrients needed and cause malnutrition.