Each healthy green leaf you remove will reduce your plants capacity to produce energy. A reduction in energy will slow growth and can result in smaller plants/flowers. Defoliation is a theory that should have died out with the dinosaurs. Why anyone would want to remove a beautiful, healthy green leaf that their plant has spent so much time and energy to grow, and for no particular benefit to the plant, is beyond me. Those "bud sites" that people are worried about as being shaded, are actually relying on those big, green, healthy leaves to produce the energy for the "bud sites" to grow! Only yellow leaves should be removed; for by the time they are yellow, they have served their purpose.
In addition to producing energy, leaves also serve as a "storage site" for carbs, sugars, amino acids etc that your plant will draw upon during flowering as a ready source of these vital growth elements, rather than making them from new, during high energy requiring activity, such as flowering. By removing healthy green leaves, you not only slow her growth through reduced capacity to produce energy, you are also robbing her of her carefully "stored" vital growth elements. Therefore your plant receives two negative impacts induced through the removal of healthy green leaves. Remember; fewer healthy green leaves = lower energy production = slower/smaller growth. It is basic plant biology. Also, despite what others may think, plants can not "channel" energy, all energy is used throughout the entire plant. Plants do not have brains. Plants can not make conscious decisions. There are no energy highways with little policemen directing where energy should go. This is another dinosaur theory.
After growing cannabis for 35+ years, I am yet to see a plant that gets rid of her own healthy green leaves. Plants do however lose their old yellow leaves, this is normal. A plant dropping/removing healthy green leaves is not normal. Hundreds of thousands of years of evolution has resulted in a cannabis plant that is at its peak of perfection. Everything the plant does is in order to grow her best flowers, reproduce and keep surviving. Getting rid of healthy green leaves has no pace in your plants ability to grow her best flowers. As you can tell, my opinion of "de-leafing" is very much anti, and I recommend you leave all healthy green leaves on your plant and to only remove yellow leaves. This way she can produce maximum energy, which results in maximum growth. It is that simple! Sorry for the rant, but I feel better now that I have had my daily dose of "anti leaf removal" venting!
Hope this helps you or others that may read this.,....
Organoman.
Again... fewer healthy green leaves = less energy production = slower and smaller growth.
P.S. - I do however believe in some gentle and well considered "lollipopping" as being a beneficial technique. In this case/method, I try to remove the inner smaller flowers, while still leaving the inner leaves in place to continue providing energy and to act as food reserves for when the plant is flowering.