To learn more about what's happening on the International Space Station at any given time, check out NASA's frequently-updated ISS blog or their page about the research and development work happening on ISS.
Depends on your body type and metabolism and your routine. But usually it takes around 3 to 4 weeks for visible results. For me it took me a couple of months to actually see any progress visually.
How quickly you will see a weight-loss result from exercising depends on a couple of factors, including the frequency of your workouts and the amount of calories you burn during your workouts. The American Council on Exercise recommends that you exercise 30 to 60 minutes most days per week in order to burn enough calories to lose weight.