Today on What’s Good Food You, Slats sets out to see if exercise make you hungry. He works up a sweat, but will he work up an appetite? Leila gets the low-down on what is lurking under your nails while Brooke tackles the painful problem of muscle cramps. We all want to live longer but what’s the real secret to longevity? And is it safe to re-use plastic water bottles? Guest reporter Jessica Rowe discovers water isn’t as clean as it looks.