Name a sign that may suggest an infant is not feeding adequately.

Insufficient weight gain or failure to thrive is an important sign that may indicate an infant is not feeding adequately. When an infant is not receiving enough nourishment, it can result in inadequate weight gain, which is a critical indicator of feeding issues. Growth and development in infants are closely monitored through regular weight checks; if an infant fails to gain weight appropriately or shows signs of not thriving, it often signals that their nutritional needs are not being met.

The other options do not directly correlate with adequate feeding practices. Increased energy and playfulness might actually suggest good feeding, as a well-nourished infant typically has the energy to engage actively. Frequent crying and discomfort could be due to a wide range of issues, including hunger, but are not definitive indicators of inadequate feeding on their own. Regular bowel movements can vary among infants and do not provide a clear assessment of feeding adequacy either, as some infants may have normal bowel patterns regardless of their nutritional intake. Therefore, the indication of insufficient weight gain or failure to thrive serves as a key clinical sign of potential feeding problems in infants.