This is an awesome book on the subject, controlling blood sugar with real food, explains everything really well, recommend it even without having GD! I've never had GD but loved the book. http://www.amazon.com/Real-Food-Gestational-Diabetes-Conventional-ebook/dp/B00S33XOH2/ref=dp_kinw_strp_1
There's a subreddit for Gestational Diabetes. I really recommend checking it out. Also, this book helped me a ton because the guidelines the dietician at the hospital gave me literally were from the 60s and super outdated and awful. https://www.amazon.com/dp/B00S33XOH2/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1 The book has the guidelines in it and stricter blood sugar numbers, which is better for your wife and the baby. and also, if she cannot control it with diet, that's okay!! I had it and it sucked really bad. I also would caution you to ask for an extra ultrasound to check the amniotic fluid levels. If i had to do it over, I would have also just scheduled a c-section on my due date. I was induced, and it was actually dangerous because they missed that I had high amniotic fluid which is common with GD, so I had to get a c-section because there's a risk of cord prolapse. I would just stay on top of advocating for your wife if you are allowed to go to appointments with her. Also just know that NOTHING she did caused this. It happens. For me it sucked really bad. I had several meltdowns because it was so stressful. If you can help her get ready to eat easy snacks and meals that she can eat and not mess up her numbers that helps a ton. And get a bag of stuff ready for her to eat after she gives birth. When I got the "Regular Diet" on my traycard at the hospital I about cried because I was so happy. My blood sugar immediately returned to normal after giving birth and my babies blood sugar was completely fine as well.
Mine does too. I've decided to ignore them. There is nothing in bread pasta or rice that my baby needs IMHO. I do get carbs from veggies and full fat dairy and he's currently kicking the bejezus out of me so ... whatever. But I did some of my own research on this - and I found this book helpful - https://www.amazon.com/gp/product/B00S33XOH2/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
She talks about the carb requirement and why it's bunk - I also listened to her podcast.
I also liked this article - https://www.dietdoctor.com/low-carb/gestational-diabetes-pregnancy
But I did a lot of poking around and I gave myself permission to do what felt healthy. If GD is really another way of saying carbohydrate intolerance - then - I cut out carbohydrates. I'd say I'm eating closer to 50 a day but moreso later in the day. I can handle way more with dinner lunch than at breakfast.