Assessing and Estimating Energy, Protein, and Fluid Needs

What are the components of total energy expenditure (TEF)?

Resting energy expenditure, Diet induced thermogenesis, physical activity

What is the difference between basal metabolic rate and resting energy expenditure?

Basal metabolic rate is the minimum amount of energy needed to sustain life whereas resting energy expenditure is slightly higher because it may include some voluntary activity and TEF. REE is more practical to measure and most energy estimates are based on this

doubly labeled water

uses stable isotopes of water to measure the products of metabolism, used primarily in research because it is easy to administer and very precise, but also very expensive

direct calorimetry

measures direct heat from the body, rarely used because it’s an outdated method

indirect calorimetry

measures CO2 production and O2 intake, most common method used in clinical and research settings

Respiratory quotient

O2 produced/ O2 consumed

Interpret respiratory quotient data

if RQ=1.0, the patient is burning mostly CHO, which could be due to very intense exercise or overfeeding

if RQ=0.7, they are burning mostly fat

It is common to have an RQ around 0.85 if eating a mixed diet

if RQ is <0.7 or > 1.3, you need to repeat the test

What are the activity factors for the Mifflin-St Jeor?

Sedentary: 1.2 (Little to no exercise)

Lightly active: 1.375 (light exercise/ sports 1-3 days/week)

Moderately active: 1.550 (moderate exercise/ sports 3-5 days/week)

1.725: very active (hard exercise/sports 6-7 days/week)

1.900: extra active (very hard exercise/ sports + physical job)

What is the quick method of estimating dietary intake?

The quick method is not intended for use in healthy populations, and is only meant to be used in malnutrition, renal disease, and people with obesity on ventilators

Equation for nitrogen balance

N2= (dietary PRO (g)/ 6.25)-urine urea N2-4

What is nitrogen balance?

Nitrogen balance is when N2 excretion=N2 intake.

A negative nitrogen balance occurs when there is catabolism due to inadequate protein and a positive N2 balance occurs where there is anabolism due to adequate protein

Protein needs for frequent, intense exercise

1-2g PRO/kg

Protein needs for the elderly (51+)

research suggests a greater protein need for those 51+ years

1.0-1.25g PRO/kg

How do you estimate fluid needs (method 1)?

Method 1: mL/kcal (2200 kcal→2200 mL water)

DRI adequate intake for fluid

includes water from food and beverages

Men (19+): 3.7L/d

Women (19+): 2.7 L/d

Tissue contribution to Resting Energy Expenditure

organ tissue: 60%

skeletal muscle: 20%

bone and fat mass: little effect

Best way to increase metabolism

physical activity and increasing muscle mass

Which macronutrient has the greatest TEF?

protein

How do you estimate fluid needs (method 2)?

Teenager: 40-60mL/kg; Adult: 30-35mL/kg; older adult (65+): 25mL/kg