People instinctivly try to feed them more when they ar ebeing conditioned for breeding, to give them more resources for the egg production. This sounds like common sense, but it has a catch.
Chameleons will develop more eggs if they are fed more. They live longer if they lay fewer eggs, and shorter if they lay more - it's a natural way of balancing things out. In good years, with plenty of food, they lay more eggs, taking advantage of the food, while straining themselves a bit.
In captivity, this is much more pronounced, as food is in an abundance not likely encountered in wild situations. Fat chameleons lay more eggs, and in turn, have a greater strain on their bodies. This is fine if you want to have lots of babies, and don't care so much for the individual female...but most hobbyists are not geared that way!
Keep your female healthy, but not fat,a nd she will lay good clutches of eggs. SMaller, but just as healthy - if not more so. The strain on her will be lessened, despite her getting fewer quantities of food.
What you do is keep them on a limited diet after they reach breeding age - to keep them from getting fat, and developing huge clutches (more of an issue wiht veields, but it pertains to most species ot some degree). AFTER mating, increase feedings - the # of eggs is already determined, so you don't have to worry about that. A healthy female should be able to develop eggs at a natural rate, without a drastic change in diet or supplementation.
