Heart Rate Training on Whole 30

[RoastedVeggiesaretheBest]

I'm a big believer in heart rate training and I started training for a half marathon in January.  I was cruising in my easy and long runs keeping my heart rate in Zone 2 with no problems.  10 days into my Whole 30 and my heart rate is going haywire. To keep in my zone I'm having to slow WAAAAY down and any minor hill pops me up into Zone 3 and even Zone 4!  This is really not fun and really frustrating.   What's weird is that my heart rate is registering high but I'm not feeling like I am huffing and puffing. Am I too carb deprived? I'm trying to have potatoes with dinner the night before runs.  Am I doing something wrong?

What gives?  Any heart rate trainers out there having the same experience?

[SugarcubeOD]

Workouts can get a bit wonky when you first start out as your body changes from sugar burning to fat burning.  I am not a heart rate trainer, but I do know this happens a lot.  

this program is not a 'low carb' program... if you want, list out what you've been eating for all meals and pre/post workout including portion sizes, specific veggies, protein and fat, meal timing, sleep etc... and we can see if there's something that stands out that may help while you become fat adapted.