My diet is basically vegan + meat. (Easiest way to explain it.)
Stir-fry meat and vegetables can be quite tasty and quick to prepare.
Something like mustard greens or gai lan[0] can be shredded by hand in a few moments and/or cut up almost as quickly.
Mushrooms (whole if you're in a rush, or sliced -- that only takes a minute or so), tofu (i prefer firm tofu), are also quite nice for such a dish.
And you can grill your meat/fish/poultry and saute your vegetables too.
Fresh fruit is also quite tasty.
I guess my point is that one can make tasty, healthful food quickly and easily, even if you have dietary restrictions.
In fact, those with dietary restrictions are likely better off cooking than eating prepared/pre-processed foods, as you don't have any insight/control over the kitchen/factory in which those foods are prepared.
Not telling you what to do, just sharing my experiences. I hope you find them useful.
Is that because you're vegan, or because you think it takes a long time?
I'll be having an omelette for dinner this evening and if it takes me more than 10 or so minutes to prepare, I'll be quite surprised.