I wouldn't be cutting back on carbs as thats what you need to recover from your training properly and put in the solid sessions day after day. Craving junk food if anything will be a sign of low sugar levels, ie carbs.
http://www.kenlaidlaw.pwp.blueyonder.co.uk/calorie.xls
When I started I used to use that spreadsheet to give me a rough idea of the breakdown on food I should be targeting over the course of a day. About 1 week in every 3 months or so I record what I eat to give me a feel for what I should be eating on a regular basis. It's pretty basic but it's a start.
You should really be trying to eat after any of your sessions that are about 60mins upwards and even some shorter ones if they have been hard sessions. Preferably within an hour or less of finishing.
Hope that helps a little.