Which of the following is most suggestive of malnutrition?

• A. Voluntary BMI change from 30 to 25 over 6 months
• B. Albumin decrease from 4.0 to 3.5
• C. Involuntary weight loss of 10% usual body weight over 6 months
• D. 10th percentile of tricep skinfold thickness

Answer: (C)

Unintentional weight loss is the strongest signal of malnutrition among these indicators because it directly shows a loss of body reserves. A 10% reduction in usual body weight over six months indicates a substantial energy deficit and loss of lean mass, which are hallmark features of malnutrition, especially when there isn’t a clear, intentional reason for weight change.

Other indicators can be influenced by factors unrelated to nutritional status. A voluntary change in BMI may reflect an intentional diet or lifestyle change rather than a pathological depletion of stores. Albumin levels drop for many reasons beyond nutrition, including inflammation, hydration status, and liver function, so a small decrease from 4.0 to 3.5 g/dL isn’t specific for malnutrition. A lower tricep skinfold thickness points to reduced subcutaneous fat but can occur in people who are not malnourished or due to measurement variability; it doesn’t by itself establish malnutrition without considering intake and weight change.

Thus, the involuntary weight loss over six months best indicates malnutrition in this set of signals.