I have gotten such relief from gluten free eating, but wonder whether I’m going to need to go dairy free too. Also, I’ve since been diagnosed with gout (THAAANKS FIBRO!) the FODMAP diet is also recommended for that.
One thing is using a corn tortilla (not flour, alas:cry:) to wrap sautéed fajita veggies, (or roasted veggies, see below) or those plus some meat in lieu of a sandwich with regular bread. Can be done cold if you have to take it to work or school, and assemble in the wrap when it’s time to eat. That’s easy to do ahead. Sometimes, I use a bit of mayo + a little Dijon mustard (or, leave that out) to stick it together so it will hold together in that tortilla roll-up. Think of a potato salad kind of thing, but with nearly anything in it. You could, for that matter, use diced chicken, or pork loin or chops, with just enough mayo to provide “adhesive”. Please pardon my irreverence with the culinary process. I get some of it from my ridiculous baby brother who is quite literally a world-class chef. He, for instance, refers to mayonnaise for a sandwich as “throat wax.” (But he’s also a James Beard Award-winner, and a gracious compliment-recipient from the late, great Julia Child. I can brag on him shamelessly because you don’t know me, or his name. 
But don’t tell my mom, she still wouldn’t approve.)
GF convenience foods have had me eating too much stuff with sugar and fat, because there are some yummy snacks along those lines. There’s a table sugar substitute called Erythrose (brand names include “Swerve”) which is great for drinks, baking, everything, and it doesn’t have any glycemic impact. It is a sugar, but has the advantage of not causing the above problems. (However, warning: over-consuming erythrose can have side effects like, ahem, diarrhea.) Raw veggie snacks are great, celery stuffed with that tofu-based cream cheese (sorry, brain fog won’t let me tell you the name) [edit: Tofutti is the name] seasoned with either a bit of garlic or onion powder or good seasons Italian dressing mix is delicious. Also, celery with peanut butter, yummy!
I use plenty of frozen vegetables that can be popped in the microwave, as frozen produce is frequently still in possession of its nutrients, more so than the produce aisle, because it’s frozen very quickly after harvest.
One thing that can be done ahead and reheated is veggies roasted in the oven with olive oil and garlic, like diced sweet or white potatoes, Brussels sprouts, broccoli, and more. Roast them at a fairly high heat and turn them with a spatula partway through: always extra delicious when a bit of brown can be achieved. As I mentioned above, while delicious hot, they can also be given the potato salad treatment and served cold. In which case, chopped celery and/or onion may also be in order. Don’t be shy about any omega-3 rich fats, like the olive oil, or a cold salad of avocado and tomato with some olive oil and red balsamic vinegar (I eat a whole avocado at a time, just because I can). Get one of those avocado tools, which will make you so happy. Pampered Chef has them, and surely someone else does for half the price.
Thought not particularly good for do-ahead, spinach and/or chard is very quick to wilt down with olive oil, or o.o. + butter or ghee in a skillet and eaten immediately. Cook that only until JUST barely shrunk down, or else it’ll taste just like what you hated about it in childhood.
Here I’ve gone on like I know what I’m talking about, but I’m just a pretty ordinary home cook. Maybe you’ll see something you like here, or it’ll give you an idea for something related.
Though I still mourn gluten, and noisily, at the end of the day nothing tastes as good as being pain and fatigue-free (or improved) feels.
Xxoo
hmmm, fruit popsicals sound ultra appetizing considering we are dealing with 90 degree weather right now. I will definitely add that to my “menu” for the next couple weeks.