A couple of thoughts:
If the DF hasn't disrupted her sleep yet, it probably isn't now.
There's a growth spurt around 6 months, have you hit that yet? That might explain some of your issues. 2 nights isn't really enough to be a habit yet, that might be waking out of genuine need. Will she settle right back to sleep after a feed? My dd2 and ds both needed night feeds until close to a year and I found that if they took big full feeds and settled right back to sleep after, then they were only waking up for hunger -- if, after the feed, they still had trouble settling, then I would look for other reasons for waking.
The "upping carbs" thing sounds weird. Honestly, if anything would make her be settled for longer, it would be some good fats, like avocados. However, nutritionally speaking, breast milk has more fat and calories ounce for ounce than any food you'd feed her anyway.
If you feel that it truly is a habitual waking, there are some good tips here on how to address it:
http://babywhispererforums.com/index.php?topic=213387.0