Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Cliff indigestion

I have tried several Cliff products over the years, none with good results. For whatever reason, these things do not sit well in my stomach. Perhaps it is all of the years of living on Mac n Cheese but these organic and "easy to digest" products are all but. I tried the Bloks at a pre-race expo and the thing sat like a rock in my gut. They taste all right but wow are they tough to digest.