it can be because of some tmj problems,do u have any history of trauma to mandible or to face ?it can also be due to some occlusal discrepency
You might get an ESR rate to see if it is up, indicating there might be inflammation in a blood vessel there. Temporal arteritis or something. Your blood pressure does go up when you eat, which could cause increased pressure in the temporal artery. If it is inflamed- you'll want to find out why- is there plaque build up that could lead to a TIA (transient ischemic attack) or a full blown stroke?
There might be a TMJ (temporal mandibular jaw) connection, since dysfunction with TMJ (it can affect one side) can give pain in the temple plus you say it happens after you eat.