Final answer:
The correct statement that reflects the guardians' understanding of dietary education for their 3-year-old is about switching to lower-fat milk from whole milk. This shows awareness of the suitability of milk types for young children and acknowledges the importance of implementing a balanced diet with physical activity for the child's health.
Step-by-step explanation:
The question relates to the dietary education provided by a home health nurse to the guardians of a 3-year-old. The guardians have made several statements, and the correct one that indicates their understanding of the nurse's dietary education would be 'Whole milk is not suitable for our child; we'll switch to skim milk.' (Option b). This statement shows an understanding that whole milk is high in fat and that a lower-fat option might be more suitable for a child beyond the infancy stage. We need to note that mature milk, like what a breastfeeding mother produces, changes in composition from the beginning (foremilk) to the end (hindmilk) of a feeding. Foremilk is mainly to quench thirst while hindmilk is rich in fat which satisfies hunger.
For infants, cow's milk is not recommended as it is difficult to digest, and it should never be introduced before 12 months of age. In addition, the importance of avoiding high-fat foods exclusively and sugary drinks is essential for preventing obesity and related illnesses such as type-2 diabetes and cardiovascular disease, aligning with the notion that physical activity and healthy eating are critical for a child's education and upbringing.