national grid customer service If required, proteins can also fulfill an energy function , being able to provide 4 kcal of energy per gram of food. However, in a balanced diet, energy should be provided mainly by carbohydrates and to a lesser extent by lipids, since proteins have these important functions that we have described in previous paragraphs. When there is no availability of carbohydrates or lipids, the body has a process called gluconeogenesis , through which the amino acids are transformed into glucose. For those who seek to develop their body mass, it is not convenient to reach this point, because proteins are destroyed to generate energy instead of building muscle. Protein requirements in the body Those who seek muscle hypertrophy need a higher protein intake than sedentary people.