Could diet foods be making you fatter? How do we learn to like the foods we eat? This week, we indulge in the science of appetite, diet and diabetes. We'll find out how our early experiences of food can alter our diets for life, and ask if low calorie alternatives to sweet and fatty foods can fool the brain into underestimating the energy content of the real thing. Also, how synthetic chemists are searching for compounds to monitor blood glucose and control diabetes. Plus, how regions of the brain can "catch" Alzheimer's from each other, we discover a new microscopy technique that can open a window on the brain in action, and talk to the Australian ecologist who thinks more introduced species, including elephants, could stabilise the Aussie ecosystem.