insulin resistance The Journal of Applied Physiology study insulin sensitivity insulin resistance tudy tudy الصيام يحسن فاعلية الإنسولين Halberg et al., 2005 tudy tudy insulin sensitivity http://jap.physiology.org/content/99/6/2128 tudy http://jap.physiology.org/content/99/6/2128 study tudy The Journal of Applied Physiology study tudy study