DACBN cheat sheet

Clinical Nutrition

• Energy from macronutrients: carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g, and fiber roughly 2 kcal/g (1.5-2.5 depending on fermentation).

• Body weight classification uses BMI = weight (kg) / height (m)^2; underweight <18.5, normal 18.5-24.9, overweight 25.0-29.9, obesity class I 30.0-34.9, class II 35.0-39.9, class III >=40.0 kg/m^2.

• Ideal body weight (Devine): men 50 kg + 2.3 kg per inch over 5 ft; women 45.5 kg + 2.3 kg per inch over 5 ft. Percent IBW and adjusted body weight (IBW + 0.25 x [actual - IBW]) are used for dosing and estimating needs in obesity.

• Estimated energy needs: 25-30 kcal/kg/day for stable adults; 30-35 kcal/kg/day for hypermetabolic states (burns, sepsis, trauma); 20-25 kcal/kg/day for obesity with weight loss goals. Protein: 0.8 g/kg/day healthy adults, 1.2-2.0 g/kg/day in stress or critical illness, 1.0-1.5 g/kg/day in chronic kidney disease without dialysis.

• Nitrogen balance = nitrogen intake - (urinary urea nitrogen + 4 g for insensible and non-urea losses); positive balance indicates anabolism, negative indicates catabolism or inadequate intake.

• Refeeding syndrome risk: start feeding at 10-20 kcal/kg/day with thiamine (100 mg) before feeding, correct phosphate, potassium, and magnesium; monitor electrolytes daily for the first week in high-risk patients (BMI <16, minimal intake >5-10 days, chronic alcohol use).

• Enteral nutrition is preferred over parenteral when the gut works; contraindications include mechanical obstruction, severe ileus, and high-output fistula. Parenteral nutrition indications include short bowel syndrome, severe malabsorption, and prolonged ileus.

• Respiratory quotient (RQ): carbohydrate oxidation ~1.0, fat ~0.7, protein ~0.8, mixed diet ~0.85; RQ >1.0 suggests overfeeding with lipogenesis.

• Micronutrient reference values: vitamin D 600-800 IU/day for adults, calcium 1,000-1,200 mg/day, iron 8 mg/day men and 18 mg/day menstruating women, folate 400 mcg/day (600 mcg in pregnancy).