I really recommend joining the facebook group and reading through this website in great detail: https://www.gestationaldiabetes.co.uk/.
Basically, never eat a 'naked' carb - always pair with either a fat or a protein (or both!)
Most women with gestational diabetes are quite sensitive to carbs at breakfast so most end up having eggs or full fat greek yogurt with blueberries and nuts (or something along those lines). You can also eat one of the cakes with the weird sweeteners for breakfast if you have a sweet tooth - many do.
Snack on babybel cheeses, ham or similar - you can eat as much as you want. Eat little and often to keep your blood sugars stable, loads of fats and proteins to feel full.
Every day I ate:
- full fat greek yogurt with blueberries and nuts (breakfast 1)
- 3 scrambled eggs in butter and cheese on one small dense piece of seeded toast with butter (breakfast 2)
- haloumi or other cheese with refried beans, chicken, guacamole, olives, lettuce (lunch)
- bowl of green apple and blueberries and full fat cream (snack)
- steak, gravy 2/3 new potatoes and broccoli (dinner)
I drank diet coke, other 'diet' drinks (don't affect blood sugars), black coffee, and water.
I tried apple cider vinegar shots after dinner as those are recommended (I soon stopped, but you can try). I also did dancing after dinner for the first month or so as my resting numbers tended to be worst, but as I sorted out my diet and ate the same thing every day, it all settled out.
I, like many pregnant women, didn't gain a kg after my diagnosis despite eating unbelievable amounts of food and fat and going from my 2nd trimester to 3rd.
I was in great shape by the end. It's basically a high protein and low carb diet, boring as hell, but I noticed reduced puffiness in my face as well - it's quite good for you I think?
I managed to stay diet controlled, despite a few high readings early on. Good luck to you.