At first, the students read the definition of BMI (Body Mass Index) and discovered how important this index is to estimatea person's nutritional status. The document presented a classification based on BMI intervals, and a scale of risks according to the level of BMI, either too high or too low. Then the students applied a mathematical formula to calculate the BMI of examples of people, knowing their weight and height. In return, using a spreadsheet software, they tested values, compared numbers and calculated the height or the weight of a person, knowing their BMI.
In a second step, the students discovered the principle of proportionality in a context linked with health and they realized the influence of our diet on our health condition and energy, perceive the importance of eating a balanced diet and having a proper breakfast. They calculated the energy intake of some foodstuffs, then they converted their energetic values either into kilocalories, or in kilojoules. They set rules to improve the lifestyle.