As the others alluded to, the leaves are the major part of the plant that is photosynthesizing and thus producing the energy and other vital compounds. The leaves are playing a major role in the production of the buds themselves, especially the big fan leaves. Also, while it may look to you like a big leaf is shading out a bud or lower branch, a lot [most] of the light is actually passing right thru that leaf to be absorbed by the other leaves and plant parts.
Of course, due to physics and the inverse square law which pertains to light; the amount of light energy received is, in the simplest terms, exponentially less intense the further away from the source you go. So, at 4 feet away from the lamp there is no more than 1\4th the intensity of light as there would be at 2 feet from the lamp and so on. This means that no matter how many leaves are or are not 'in the way', if you have a 4 foot plant it's lower branches will never receive anywhere near the same intensity of light energy as the top or middle of the plant is getting.
A better solution to fussing with the leaves would perhaps be to add in some side lighting, such as some higher wattage CFLs or tube fluorescent bulbs (T5s, etc).