How would melanoma cause weight loss?

Cancer Cachexia: Early melanoma or any other cancer may not cause weight loss. As the tumor progresses, there are multiple ways it causes weight loss, e., g., loss of appetite, increased catabolic rate, and poor absorption etc. Consult this site for more info. http://www.ncbi.nlm.nih.gov/pubmed/3292798 For good health - Have a diet rich in fresh vegetables, fruits, whole grains, low fat milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.