Why are you just sticking to insects?? I feed mine collards, dandelions, kale, endive, escarole, squash, sweet red pepper, sweet potato, zucchini, and a small amount of apple, pear, melon, berries.
If your veiled won't eat them when fed them, the same things are good to gutload/feed to crickets, superworms, roaches, etc. so your chameleon will get them whether he eats them or the insects.
Its also important to dust properly. Since most insects have a poor ratio of calcium to phosphorus, its important to dust the insects just before feeding them to the chameleon with a phos.-free calcium powder to make up for it. (I use Rep-cal).
I dust twice a month with a phos.-free calcium/D3 powder to ensure that they get some D3 without going overboard. I leave them to produce the rest of the D3 from exposure to their UVB light (a long linear fluorescent Repti-sun 5.0 tube light. The UVB should not pass through glass or plastic). D3 from supplements can build up in the system...but D3 produced from exposure to UVB shouldn't as long as the chameleon can move in and out of the UVB.
I also dust with a vitamin powder that has a beta carotene (prOformed) source of vitamin A. Beta carotene won't build up in the system like prEfromed sources will...but there is controversy as to whether all/any chameleons can convert it...so some people give a little prEformed once in a while. Excess preformed may prevent the D3 from doing its job and push the chameleon towards MBD...so don't overdo it.
Calcium, phos., D3 and vitamin A are all important players in bone health and need to be in balance. When trying to balance them, you need to look at the supplements you use and what you feed the insects and the chameleon.
Appropriate temperatures also play a part in that they aid in digestion and thus indirectly in nutrient absorption.
Sorry this is long, but so many people miss doing things that are important regarding feeding.
