In the last months, we have to read a lot of food problems.
The mainproblem was most of the time missing proteins. Nearly all species need it in great amounts. Users with strange foodtests or people who give them only sugar water is quite often lately...
Flies are the best, insects with hard protection are often uninteresting. A lot of bugs arent so good. Small colonies arent capable to open them.
Sugar water, mixed sugar water with honey (try different sorts) and insects.
We can read a lot uncommon food, but dont try that. It could kill your ants. The best example are apples from the supermarket, often sprayed with a lot of chemicals.
Also in a lot of posts we can read, that a variation of testfood was accepted and transported into the nest. That doesnt mean they eat it and would be in the nest until it learn to walk

So, insects (flies) and sugar water (honey) are all they need as food.