Two friends recently used the LGW-YYZ and return on WestJet and found all aspects (in Y) to be just fine. Execept food details.
Both of them asked what was in the meals oferred. The CC did not know. They asked to see the list of allergens list. This drew a blank. As one of the pax has worked in commercial catering for many years - they knew what they were expecting to see. In the end, they ate little of the food and had taken the precaution of bringing food with them.
I have just looked through the WestJet website and the details are scant other than:
WestJet food products may contain traces of peanuts or other allergens.
But the crew had no detail or support to offer. No alternatives. If you have known allergies, you might want to be careful and take your own food.