More than a third of adolescents are overweight or obese. Others suffer from inadequate nutritional intake or slow growth. Careful evaluation of nutrition and growth are essential aspects of adolescent medicine. Obesity is multifactorial and rarely just the result of bad behavioral choices by the patient. Treatment of obesity depends on clear clinician-adolescent communication and the involvement of a supportive team; new medications can be very helpful, and bariatric surgery is a reasonable option for many adolescents. Lack of appropriate weight gain can be due to inadequate intake related to an inappropriate body image as seen in patients with anorexia nervosa; family-based therapy with modification of eating behaviors and careful monitoring can be helpful but takes time. Athletes with restricted intake (relative energy deficiency in sport) and patients with post-abdominal discomfort avoidant restrictive food intake disorder can respond to dietary changes. Physiologic shortness should be differentiated from short stature due to genetic and hormonal causes so specific management can be customized to individual patient needs. Vitamin D deficiency and iron deficiency are also very common in adolescents; depending on the setting, widespread supplementation and/or individualized diagnosis and treatment can be appropriate.