There are several! But, the best one is stomach crunches. If you are looking to lose stomach fat or build your stomach muscles then you should go in for stomach and abdomen crunches. But remember that these are extremely painful and the first few days will be extremely tough. Once you get past the difficult stages, then it will be much easier to work out on a daily basis. You must start off with 30 crunches a day and steadily increase it to around 50. Over a period of time you can increase the number of crunches to around 100 and split it into two work outs.