We always go with a strict shopping list and we never wander around in the shop. The only exception is when we're looking for some special product, something we've never bought before, but even in this case our rules are very strict and we never buy anything that is not McDougall friendly.
If you have any further questions, feel free to ask, but you'll get an answer much faster if you post your question to a more appropriate forum, like the forum called
A Place for Newbies which is the 8th forum on the
index page.
Hope it helps
grid