That is EXACTLY what I have been experiencing as well. In fact, I just posted that same question in my thread ("increased risk of ovarian and breast cancer?"). It is especially noticable at night, or when I am not active. I can almost feel my heart pound in my throat. Loud, heavy thumping. Scared me to death last night, thought for sure I was going to die. I have been feeling it ever since I started this diet 5 days ago. I guess it makes me feel a little better knowing that others experience the same thing. The question remains though: is it something we have to worry about?