Uh…I haven’t seen any definitive research on this. I base my claims on personal experience. I get about 25–35 lbs of tomatoes per plant (conservatively estimated), and I fit more plants into less space than is typical (10 tomato plants in a 6' x 14' space). Do you get about that much too? If so, than it’s one example that cutting it back isn’t necessary. Would love to hear about it. Thanks.