<<Disclaimer: Verify this information before applying it to your situation.>> As I remember the Aitken's diet, it would be virtually gluten free because it required eating a high level of proteins and fats and virtually zero carbs. Your body goes into ketosis because you are "living off" fat and protein for energy, something that is normally provided by carbs. In fact, you were supposed to buy keto sticks at a pharmacy to check your urine for ketones, an indication that the "diet" was "working". The drawback to the diet was that the minute you went off of it, and started eating a normal diet, that included carbs., you would gain the weight back. In this day and age, with all we know about fat, it's obviously not at all healthy...but I suppose it was virtually free of gluten.