Eating soy products can damage your thyroid. After being on this diet for quite a while and eating lots of the bars and shakes which usually contain alot of soy, I found I was cold all the time. I have stopped eating those foods, and eat whole foods for the most part now, and I take a supplement of kelp, which contains iodine, which helps the thyroid. Within 2 days of taking kelp, I started to be much warmer and almost never get cold anymore.