What is the estimated daily energy requirement for a 64-year-old male, 49kg, 162cm, with severe stress, and how many servings of a 383.48 kcal/100g milk supplement are needed?

Calculating Basal Energy Expenditure and Nutritional Requirements

Direct Answer

For this 64-year-old male (49kg, 162cm) with severe stress, the total daily energy requirement is approximately 2,205-2,940 kcal/day, requiring 11.5-15.3 servings of the milk supplement daily. 1

Step-by-Step Calculation

Step 1: Calculate Basal Energy Expenditure (BEE)

Using the Harris-Benedict equation for men: 1

• BEE = 66.4730 + (13.7516 × 49kg) + (5.0033 × 162cm) - (6.7550 × 64 years)
• BEE = 66.4730 + 673.83 + 810.53 - 432.32
• BEE = 1,118.5 kcal/day

However, given this patient's age (≥65 years threshold is close) and severely underweight status (BMI = 18.7 kg/m²), an alternative simplified approach is appropriate: 2

• REE = 18-20 kcal/kg/day × 49kg = 882-980 kcal/day 2

For severely underweight patients specifically, ESPEN recommends: 2

• REE = 30 kcal/kg × 49kg = 1,470 kcal/day 2

Step 2: Apply Severe Stress Factor

Under conditions of severe stress, energy requirements approach 30 kcal/kg ideal body weight, with stress factors of 1.5-2.0 applied to basal requirements. 2, 1

Using the severely underweight patient calculation: 1

• Total Energy Expenditure (TEE) = 1,470 kcal × 1.5 to 2.0
• TEE = 2,205-2,940 kcal/day 1

Step 3: Calculate Milk Supplement Servings

Given milk supplement specifications: 1

• 383.48 kcal per 100g
• 5 scoops = 50g = 191.74 kcal per serving

Number of servings needed: 1

• Lower range: 2,205 kcal ÷ 191.74 kcal/serving = 11.5 servings/day
• Upper range: 2,940 kcal ÷ 191.74 kcal/serving = 15.3 servings/day

Critical Clinical Considerations

Refeeding Syndrome Risk

This severely underweight patient is at extremely high risk for refeeding syndrome, and the calculated target must be achieved cautiously and slowly. 2, 1

• Start with lower caloric intake (approximately 50-70% of calculated needs) and gradually increase over 7-10 days 2, 1
• Initial target: Begin with 1,100-1,500 kcal/day (approximately 6-8 servings), then advance slowly 2
• Monitor electrolytes (phosphate, potassium, magnesium) closely during refeeding 2

Protein Requirements

Protein needs are 1.2-1.5 g/kg/day for older patients with illness/stress. 2, 1

• Target: 59-74 grams protein/day (49kg × 1.2-1.5 g/kg) 1
• Ensure the milk supplement provides adequate protein content to meet this requirement 2

Accuracy Limitations

Predictive equations have significant limitations in this population, with accuracy dropping to approximately 45% in severely malnourished patients. 1

• The Harris-Benedict equation tends to overestimate energy requirements by 10-15% in healthy individuals 3
• In elderly hospitalized patients, Harris-Benedict may underestimate requirements 4
• Indirect calorimetry is the preferred method for measuring energy expenditure if available 2, 1
• Weight-based formulas should only be used as a starting point, requiring adjustment based on clinical response 2

Monitoring Strategy

Mandatory close monitoring includes: 2, 1

• Weekly body weight assessment with intake adjustments accordingly 2, 1
• Daily electrolyte monitoring during initial refeeding phase 2
• Assessment for signs of refeeding syndrome (edema, cardiac dysfunction, respiratory distress) 2
• Re-screening nutritional status every 7-10 days 2

Common Pitfalls to Avoid

Do not provide full calculated energy requirements immediately - this is the most dangerous error in severely underweight patients with high refeeding syndrome risk. 2, 1

Do not use ideal body weight for calculations - actual body weight should be used in this severely underweight patient (49kg). 2

Do not apply stress factors rigidly - severe stress factors of 1.5-2.0 represent hypermetabolism of 110-180% above baseline, but individual variation is substantial. 2

Avoid overfeeding - hyperalimentation increases oxygen consumption, carbon dioxide production, and can cause fatty liver, particularly problematic in frail patients with low cardiac and respiratory reserve. 2