This is the website we used to teach my step-father about his diabetes and controlling his carb intake...
http://www.endocrineweb.com/diabetes/treatment.html
One key element that we wanted him to follow was "
Each gram of carbohydrate provides 4 calories. A diabetic on a 1600 calorie diet should get 50% of these calories from carbohydrate. This would be a total of 800 calories or 200 gms of carbohydrate (at 4 calories per gram) spread out over the day. At 15 grams per exchange, this would be about 13 exchanges of carbohydrate per day."
If you can teach them that exchange to follow and to avoid sugars, that should hold them over until they can see the nutritionist and set up a daily meal plan.
There's lots of other information on that website too. HTH!