gourmet, according to the dictionary is just more or less someone who knows about food and drink. In my experience, I would NEVER go to a 'gourmet' restaurant as the portions are always miniscule. To my knowledge (apart from the advertised 'all you can eat' restaurants) nobody has EVER even implied that a person should not be full on leaving!
In any case, I was always taught that one should always leave the table at the 'just less than full' level in case your hosts had an extra surprise for you.