Which of the following is not a likely cause of failure to thrive in a child?

A vegetarian diet is not typically a direct cause of failure to thrive in a child, assuming the diet is well-planned and nutritionally adequate. Many vegetarian diets can provide all the essential nutrients a child needs for healthy growth and development when carefully constructed. It is important to ensure that a vegetarian diet includes a variety of foods to supply sufficient calories, protein, vitamins, and minerals necessary for a child’s growth.

In contrast, chronic illness can significantly impede a child's ability to gain weight or grow properly, as ongoing health issues often affect metabolism, appetite, and nutrient absorption. Poor feeding practices, including inadequate feeding frequency or inappropriate food choices, can also lead to nutritional deficiencies and consequent failure to thrive. Malabsorption disorders prevent the adequate absorption of nutrients from the gastrointestinal tract, leading to deficiencies regardless of food intake, which can further contribute to failure to thrive in affected children.