Is it really necessary a caloric surplus to maximize muscle growth

Generally, yes—a caloric surplus can help maximize muscle growth, but it isn’t strictly necessary for everyone. Some people can build muscle while eating at maintenance or in a slight deficit, particularly those with higher body fat and less training experience; for most people, however, gaining muscle is more challenging without eating above maintenance. 1 2

• 1. Typical surplus: A suggested starting point is about 10% above maintenance—roughly 200–300 extra calories per day in one discussion. Another estimate gives 10–15%, or around 250–400 extra calories for someone eating 2,500 calories at maintenance. 3 4
• 2. Keep it moderate: A large “dirty bulk” isn’t required; a modest surplus avoids deliberately eating to excess and limits unnecessary fat gain. 5 6