The basic rules set by the health authorities are expressed as a function of the Recommended Nutritional Intakes (ANC), for each type of nutrient over a 24-hour day. For example, the carbohydrate ANC for an adult aged 18 to 25 is 250 g / day. These ANCs are benchmarks that we cannot always follow to the letter, in particular for reasons of schedule (lunch at a restaurant, sandwich on the go …). But, when they are achieved, they make it possible to guarantee the right nutritional balance.
Our energy needs
They differ for male or female adults and according to their level of daily activity. For a man aged 18 to 45, the recommended energy intake varies between 2,400 and 2,600 cal / day depending on his level of activity. For a woman, it should represent between 1,800 and 2,200 cal / day.
Our nutrient needs
Every day, an adult must absorb a certain amount of lipids, proteins, carbohydrates, fibers … to allow the optimal functioning of his organism. Dieticians and nutritionists recommend consuming between 45 and 50% of daily calories as carbohydrates (2/3 complex carbohydrates and 1/3 simple carbohydrates), 15% as protein, 35 to 40% in the form of lipids …
We do not all have the same energy needs
During the period of adulthood which goes from 18 to 75 years, one takes into account the age, the sex, the weight, the physical activity practiced daily and the possible health problems to establish the energy needs of each person.
In other words, to estimate the right amount of calories that we must ingest each day, the medical profession is interested, in addition to our weight, age, height …, in our level of daily physical activity. And differences are made between an individual sedentary (less than 30 minutes per day of sustained physical activity in addition to daily activities), moderately active (between 30 and 60 minutes per day) or active (more than 60 minutes per day).
Some examples :
• The energy requirements of a sedentary 35-year-old man are about 2,400 cal / day, but they increase to 3,000 cal for an active adult of the same age.
• The energy requirements of an active 35-year-old woman are approximately 2,200 cal / day while that of a fully sedentary woman of the same age should not exceed 1,800 cal / day.
This nuance, sometimes important since it represents a difference of about 400 to 600 cal between a sedentary person and an active one, can be further accentuated if the person is overweight, obese … The dietitian or the nutritionist can then choose reduce calorie intake, at least over a period of time.