Hello, it is ok to do sit-ups with thin abdomen, but it will take some time to have an effect. In addition, eat less sugary and fatty things in your diet. It is best to eat a plastic fiber fruit half an hour after dinner every day. Slimming factors extracted from many natural herbs can not only burn body fat quickly, but also have a certain effect on breast enhancement. A small plastic fiber fruit can burn the same amount of fat as running for three hours every day, so it's good for you to be lazy and lose weight.