A person is considered thin when their height and weight are out of proportion. If you experience a sudden decrease or increase in appetite, you should look for the cause, as it could be due to illness or other health problems. The cause: malnutrition and a food quality that does not meet the body's needs (carbohydrates, proteins, lipids, vitamins A - D - E - K). Hygiene and health" programme, broadcast on Don Bosco radio.