The phrase "main macronutrients" refers to the three essential nutrients that our bodies need in large quantities to properly function and stay healthy. These nutrients are carbohydrates, proteins, and fats. Full definition
Protein is one of the 3 main macronutrients as we know it. (blog.oziva.in)
As long as you consume a slight caloric surplus, and stick to a clean and lean diet primarily consisting of the three main macronutrients then you should start to see the results you want. (infinitelifefitness.com)
The three main macronutrients from which energy is supplied, include: Carbohydrate, Protein, and Fat. (hoffmansfitness.com)