A BMI under 18.5 is considered unhealthy. There is risk that you are not getting sufficient nutrition (malnutrition). Complications of malnutrition include anemia, nutrient deficiency, heart irregularities, loss of menstrual periods in women (amenorrhea), cavities, and osteoporosis.
Author: Healthwise Staff Medical Review: E. Gregory Thompson, MD - Internal Medicine Brian O'Brien, MD, FRCPC - Internal Medicine Kathleen Romito, MD - Family Medicine Martin J. Gabica, MD - Family Medicine Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator
Medical Review:E. Gregory Thompson, MD - Internal Medicine & Brian O'Brien, MD, FRCPC - Internal Medicine & Kathleen Romito, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator