Hi,
For a rescue that isn't yet eating his staple well...I would limit the meal worms. They aren't an important part of the diet, although yes they do contain some protein, they are mostly fat. You didn't mention how many you're giving but depending on his size...maybe give him a few in the morning 3-5 count, so that he has had the opportunity to eat what he really needs of his staple and fruits and veg at night. Or, you could alternate nights and not offer as many and don't offer them every single night. Pretty much ALL suggies (there are exceptions) would prefer to eat a diet of ALL mealies.
Like a kid in the candy store.