Chanko Diet and Heartburn/Indigestion

Hi there,
I was trying to eat more rice after reading TC’s Chanko Diet, but I encounter one unusual obstacle. I was preparing the blend of 3 different types of rice (wild rice plus two different types of brown rice, bought at the local My Org. Market) in my Rice Cooker. It was delicious and handy, but after a while I noticed that I started to have indigestion after eating the rice. I mixed it with salmon, tuna, and chicken, no sauces, and the result was the same. I always thought that rice is a pretty safe food, and moreover this blend is supposedly organic. Maybe my stomach is too spoiled and cannot process wild rice? (I am making it “al dente”, so to speak). What can cause this? As soon as I stop eating rice (but continue with chicken/tuna/salmon) I do not have any problems. Anyone encountered this? I tried ginger and digestive enzymes, they do not help.
Your opinions/suggestions are appreciated.