I had the same thing happen OP: tried heavy cream just a bit here and there in my coffee, and it wreaked havoc on me. Half & half works a lot better on me. I haven't tried it with ice cream or chocolate syrup, but I do like it with root beer - tastes like a float!
I haven't done it long-term, so I can't say what effect it's had on me. But it sure tastes good!
8 years