Hmm, the fact that you are still eating wheat makes hypoglycemia more likely. If you were fully keto-adapted it would be unlikely (unless you are diabetic or pre-diabetic), but if you are still cycling carbs in and out, it can't be ruled out. Have you considered going continuously low carb?

Did the trainer test your blood glucose? Or is he just assuming that everyone that eats low carb suffers from hypoglycemia?