energy_total: Total energy value of the product
In FUTUR-TEAM/Future: Package with Shinyapp for Creating Meals

Function for calculating the total energy value of a product

1	energy_total(weight_of_product, protein, fat, carbohydrates, fiber = 0)

`weight_of_product`	numeric, weight of used product
`protein`	numeric, protein content in the product for which we calculate the energy value expressed in grams
`fat`	numeric, fat content in the product for which we calculate the energy value expressed in grams
`carbohydrates`	numeric, carbohydrates content in the product for which we calculate the energy value expressed in grams
`fiber`	numeric, fiber content in the product for which we calculate the energy value expressed in grams, 0 by default