Anorexia Nervosa or Disordered Eating: The patient's complaint of feeling lightness and disconnection from his feet when hungry, despite eating "lots of healthy food," suggests an issue with nutrient intake or absorption that isn't fully explained by the mild iron deficiency anemia alone. The regular experience of hunger could indicate inadequate caloric intake or an eating disorder, which is common in adolescents and can lead to various physical symptoms, including anemia and neurological symptoms like numbness.

Nutritional Deficiencies (e.g., Vitamin B12, Magnesium): The symptoms of numbness in hands and wrists, along with tendinosis and mild iron deficiency anemia, could suggest other nutritional deficiencies that are common in individuals with inadequate diets or malabsorption issues.
Diabetes Mellitus: Although less likely given the absence of classic symptoms like polyuria and polydipsia, diabetes can cause numbness and could potentially contribute to the patient's hunger and anemia if not well-managed.
Hypoglycemia (Reactive or Fasting): Episodes of hypoglycemia could explain the patient's feelings of lightness and disconnection when hungry, especially if the patient has an irregular eating pattern or a condition affecting glucose metabolism.

Celiac Disease: This autoimmune disorder can cause malabsorption of nutrients, leading to anemia, neurological symptoms, and potentially the patient's described symptoms. It's crucial to rule out celiac disease due to its potential for long-term complications if left untreated.
Type 1 Diabetes Mellitus with Diabetic Neuropathy: Although the patient doesn't exhibit classic symptoms of diabetes, the possibility of type 1 diabetes with early neuropathic changes cannot be overlooked, given the potential for severe consequences if not promptly diagnosed and treated.
Thyroid Disorders: Both hypothyroidism and hyperthyroidism can cause a range of symptoms including fatigue, hunger, and neurological symptoms. These conditions are critical to diagnose due to their impact on metabolism and overall health.

Ehlers-Danlos Syndrome: This genetic disorder can cause tendinosis and potentially some of the neurological symptoms the patient is experiencing, though it's less likely to be the primary cause of the patient's hunger and anemia.
Mitochondrial Myopathies: These are a group of disorders that affect the mitochondria, leading to a variety of symptoms including muscle weakness, numbness, and potentially issues with hunger and metabolism due to impaired energy production. However, these conditions are rare and would typically present with more pronounced muscle weakness and other systemic symptoms.