Patients undergoing a history and physical examination should be asked questions to help identify those high-risk patients who require further evaluation for malnutrition. Of particular importance are the regularity and availability of meals; who does the shopping and food preparation; recent changes in appetite, intake, or body weight; use of special diets or dietary supplements; use of alcohol, drugs, or medications; food preferences and food allergies; and the presence of illnesses affecting nutritional intakes, losses, or requirements. Elderly and adolescent patients, pregnant or lactating women, patients of lower socioeconomic status, and patients who are socially isolated are at particular risk for nutritional deficiencies.
Further quantification of dietary intake can be performed using a variety of techniques. Twenty-four-hour diet recalls provide rough estimates of nutrient intake. Patients are asked to describe their dietary intake over the preceding day, including snacks, beverages, and alcohol. Problems with this technique include poor patient recall, difficulties in estimating serving sizes, and the inaccuracy associated with generalizing from a single day's intake. More accurate information can be obtained by asking patients to complete a 3- to 5-day diet record. Nutrient composition can then be analyzed with the aid of standard handbooks or computer software. Although prospective and less likely to be invalidated by memory lapses, omissions are still common, and the usual difficulties in estimating serving size persist.