If you are not careful, your hours of sweating it out at the gym may have no effects on your weight loss. Before losing weight you must understand the working of the body and only after that can you be fit. A person invests a lot in his body while he/she is trying to lose that extra weight - his hardwork, energy, time and money, all of these thing will go down the drain if you keep making little mistakes while exercising. These mistakes are so small that even you will be shocked but the impact they have on your body is equally shocking. Wrong exercises, wrong diet, wrong time, wrong sleep - all of these things matter while you are desperatley trying to shed those pounds. Here are some common mistakes that are stopping you from achieving your goal.