Should the protein goal for a patient be expressed per kilogram of body weight rather than per pound?

Protein Goals Are Expressed Per Kilogram of Body Weight

Protein requirements for patients should always be calculated per kilogram (kg) of body weight, not per pound. This is the universal standard in clinical nutrition and medical practice worldwide 1.

Standard Protein Targets by Clinical Context

For Most Hospitalized Medical Patients

• Target 1.2-1.5 g protein/kg body weight/day for polymorbid medical inpatients requiring nutritional support 1
• This represents a Grade A recommendation with 100% consensus, supported by the large EFFORT trial (n=2088 patients) showing reduced 30-day mortality (OR 0.65,95% CI 0.47-0.91), improved functional status, and enhanced quality of life 1
• This is cost-effective and highly efficient for preventing body weight loss, reducing complications, and improving outcomes 2

For Patients with Severe Kidney Impairment

• Reduce to 0.8 g protein/kg/day for patients with eGFR <30 ml/min/1.73m² who are not on dialysis 1
• This is a Grade B recommendation with 96% consensus 1
• Patients with eGFR 30-59 ml/min/1.73m² can receive the standard 1.2-1.5 g/kg/day and actually show the strongest mortality benefits (OR 0.39,95% CI 0.21-0.75) 1

For Severely Malnourished Patients

• Target 1.2-1.5 g protein/kg/day, but achieve this gradually due to extreme refeeding syndrome risk 2, 3
• Energy targets of 30 kcal/kg/day must be reached slowly, not immediately 1, 3

Why Kilograms, Not Pounds

The metric system (kilograms) is the international standard because:

• All clinical research and guidelines express protein requirements per kilogram 1
• Protein metabolism and nitrogen balance studies are conducted using kg measurements 1, 4
• Converting to pounds introduces unnecessary calculation errors and confusion

Which Body Weight to Use

Use Actual Body Weight for Most Patients

• Actual body weight is the standard denominator for protein calculations 1
• Energy targets (30 kcal/kg) are also based on actual body weight 1

Special Considerations for Body Composition

• For severely underweight patients (BMI <16 kg/m²), use actual body weight but advance nutrition cautiously 1
• For patients with obesity or extreme body composition variations, fat-free mass may provide more accurate estimates, though this requires specialized measurement 5
• Corrected body weight formulas often lead to overestimation in 48-92% of patients with underweight, healthy weight, or overweight 5

Common Pitfalls to Avoid

Do Not Use 0.8 g/kg/day for Hospitalized Patients

• The 0.8 g/kg/day recommendation is the minimum RDA for healthy adults with minimal physical activity to prevent nitrogen loss 4, 6
• This is inadequate for hospitalized, polymorbid, or malnourished patients who need 1.2-1.5 g/kg/day 1, 2
• Historical nitrogen balance studies that derived the 0.8 g/kg RDA are over 70 years old and were never intended for sick patients 6

Do Not Convert to Pounds

• Never calculate protein as "grams per pound" as this creates confusion and dosing errors
• If a patient weighs 70 kg, they need 84-105 grams of protein daily (70 kg × 1.2-1.5 g/kg), not calculations based on 154 pounds

Recognize That Actual Intake Falls Short

• Even when hospitals provide 1.0 g/kg/day, actual consumption averages only 0.65 g/kg/day because 30-40% of provided food is not consumed 7
• Multiple strategies are needed: oral nutritional supplements (ONS), protein-rich menus, food fortification, and high-protein snacks 1

Monitor for Drug-Nutrient Interactions

• Polymorbid patients on multiple medications require pharmacist-assisted management plans 1
• High protein intake (>2 g/kg/day chronically) can cause digestive, renal, and vascular abnormalities in healthy adults 4