What Causes Unexplained Weight Loss Without Trying?

Unintentional weight loss means losing weight without trying. A loss of about 5% or more of body weight within 6–12 months is generally considered medically significant. Common medical causes include hyperthyroidism, which accelerates metabolism, and diabetes, which affects how your body processes nutrients. Digestive disorders like inflammatory bowel disease, celiac disease, and Crohn's disease can impair nutrient absorption. Mental health conditions such as depression and anxiety often reduce appetite significantly. Certain cancers, chronic infections, and medication side effects can also trigger unexplained weight loss. Consult a healthcare provider if you have lost about 5% or more of your body weight within 6–12 months without trying, or sooner if the weight loss is rapid or accompanied by other concerning symptoms.