The ’40:40:20′ rule, popularized by iconic bodybuilders like Arnold Schwarzenegger, is a well-known macronutrient split. This diet recommends:  – Carbohydrates: 40% of total daily calories – Protein: 40% of total daily calories – Fat: 20% of total daily calories                                         This balanced approach is celebrated for its association with successful bodybuilders and has become a staple in bodybuilding nutrition.