Final answer:
Pregnant or lactating women should not be switched to low-fat milk due to higher nutritional needs, including healthy fats, calcium, and iron. Older adults may need the additional nutrients in whole milk for recovery and maintaining bone density. A one-year-old should not have cow's milk regardless of weight, and a five-year-old active boy can have low-fat milk if desired.
Step-by-step explanation:
Of the individuals listed, pregnant or lactating women should not be given low-fat milk as they have increased needs for certain nutrients including fat. Fat is essential for the development of the baby's nervous system and helps the body absorb fat-soluble vitamins such as A and D. Moreover, dietary fats are also important for lactation. Pregnant and lactating women, as well as premenopausal women, need extra calcium and iron, which may be found in higher concentrations in whole milk products compared to low fat.
Older adults, such as an 80-year-old man recovering from a stroke, may also benefit from the additional nutrients found in whole milk to help with recovery and to maintain bone density, unless there are specific dietary restrictions from a healthcare provider.
For a 1-year-old girl, cow's milk should not be given until she is at least one year old due to digestive challenges with cow's milk proteins. After one year, whole milk is generally recommended for children until the age of two to support brain development. Therefore, a 'chunky' appearance would not disqualify her from whole milk, unless otherwise advised by a pediatrician.
The five-year-old boy who plays hockey would be able to have low-fat milk if desired, as he is beyond the toddler age and likely getting fats from other dietary sources to support his active lifestyle.