So Cassie has been really gassy and is very constipated from the rice in her bottle. Also tried oatmeal and that was the same. I’m wanting to try a beverage thickener. Which would be best. I’ve looked up simply thick? thick it? and thicken up? I know that thick it has a good amount of calories… thick it doesnt, and thicken up I am not sure. She needs calories bad!! She doesnt gain any weight. So any feedback would be great!! thanks