**Study Overview** The UNCOVER study is looking at patients with certain types of cancer that are at high risk of developing a condition called *cachexia*. Cachexia is a serious problem where people lose a lot of weight, muscle, and fat, which makes them weaker and can lower their quality of life. This study will observe up to 800 people with advanced lung, pancreatic, or colorectal cancer. Researchers want to learn more about different types of cachexia to help create better treatments and care plans. **Key Points:** - **Study Duration and Visits**: This is a long-term study, meaning it will track changes over time. - **Eligibility**: You need to have certain types of cancer and be starting or have recently started cancer treatment. - **Risks and Benefits**: There are no direct treatments or interventions provided in this study, but the information gathered may help improve future care for others with similar conditions. This study is designed to improve understanding and treatment of cancer-related weight loss. Participants must be over 18, able to communicate in English, and not have planned major surgeries soon.