For a 73-year-old client with a history of protein malnutrition, what initial information should the nurse obtain?

The correct choice focuses on gathering a comprehensive dietary history by asking about foods and liquids consumed during the past 24 hours. This information is crucial because it provides a detailed snapshot of the client's current nutritional intake, which can help identify any immediate deficiencies or dietary patterns contributing to their protein malnutrition.

Collecting this data allows the nurse to assess the client's actual consumption levels, which may differ significantly from what the client perceives they are eating or what they usually consume. This recent intake information is essential for tailoring nutritional interventions effectively and addressing any specific gaps in their diet that could exacerbate their malnutrition.

The other options, while informative, are less effective for an initial assessment. For instance, asking about the amount of liquid protein supplements consumed daily may only capture one aspect of their intake rather than providing a holistic view of their overall nutrition. Similarly, inquiring about the usual weekly intake of milk products and red meats or the combinations of grains and legumes used focuses more on long-term dietary habits rather than their immediate nutritional status, which is more relevant in a malnutrition context.