Need help with starting to weigh food please!

Toast isn't caused by sugars in bread being caramelized. Toast is caused by the Maillaird Reaction, which is a chemical reaction between amino acids and reducing sugars, and requires heat. Here's a somewhat decent (ie, easy-ish to understand) explanation of the differences: http://thehealthydoc.blogspot.com/2010/08/browning-vs-caramelizing.html