thanks for paging me, @MarieB!
In my experience, OBs have a one size fits all plan for GD or T2 pregnancies. It doesn't work for everybody! Throughout my pregnancy, I worked very closely with my endo instead of relying on what the OB recommended, it just worked better for me. I checked my blood sugar about 6 or 7 times a day and ate to my meter. I was constantly adjusting my insulin. I basically told my OB (I saw a MFM for high risk pregnancy) that I was managing my diabetes with the endocrinologist and that my numbers looked great. I maintained a 5.4 - 5.6% A1C throughout pregnancy and had a totally normal baby.
I think 45 g of carbs per meal sounds like way too much for your friend. It's so hard when you end up eating to your insulin, instead of the other way around. That happened to me, especially for overnights. In order not to go wayyyy low over night, and still hit my fasting target of below 90, I had to take a lot of NPH and eat kind of a big carb-y meal. It took a long time for me to figure out what worked for me!
So, I'm not a doctor. I had a lot of pressure on me to maintain a good A1C (because man, those doctors can be scary). The risks of a high A1C during pregnancy are real. Anyways, I prioritized stabilizing my blood sugar over whatever the OB/MFM said about eating a lot of carbs. That just doesn't work for me... can't have it both ways (all the carbs AND regular blood sugar???).
Not that this means anything, but I had a very healthy and totally average size baby!
Finally, one last thing I will say: informed consent. You (or your friend, in this case) are in charge of your own health care. Sometimes it seems like when there's a baby involved that maybe it's not really your choice. But it is. So do some research, consult with an endocrinologist, and make a decision that works for you.