No, we're not talking about the good kind of weight loss that you want. Instead, we're talking about sustained, unexplainable weight loss. If you tend to follow a healthy diet, you should lose weight at a pretty steady pace. However, you may notice that the pounds are really melting away, and you quickly get past your desired body weight. You continue losing weight, but there is no visible cause of the weight loss. [caption id="" align="aligncenter" width="595"] Source: laurasummers.co.uk[/caption] Cancer could be that cause! Roughly 40% of people diagnosed with cancer experience weight loss with no visible explanation. In cases of advanced or incurable cancer, serious weight loss occurred in up to 80% of people. Not all cancers result in weight loss. Doctors usually associate weight loss with lung cancer, breast cancer, and the various types of blood cancer (leukemia). If you notice that you are losing weight at an alarming rate, it may be a sign of something more serious going on inside your body. Get checked out by a doctor to find out what the cause is.