By Jennifer Turley and Joan Thompson Module 4.2 Energy Balance By Jennifer Turley and Joan Thompson © 2013 Cengage

Presentation Overview Equations States of Energy Balance Energy Intake vs. Expenditure Components of Energy Expenditure BMR, REE, PA & SDA

Principles of Energy Balance 1 pound of fat = 3500 Calories stored To lose fat/ weight: reduce Calorie intake To increase fat/ weight: increase Calorie intake Changing caloric intake for losing/ gaining weight is dependent on energy expenditure

Energy Balance Equations If Calories eaten = Calories expended -Energy balance occurs. Weight is maintained If Calories eaten > Calories expended -Positive energy balance occurs. Weight gain If Calories eaten < Calories expended -Negative energy balance occurs. Weight loss

Energy Intake Consumption of Energy Producing Nutrients in Food and Beverages Protein & Carbohydrates= 4 Cals/ g Fat= 9 Cals/ g Alcohol= 7Cals/ g Calories are calories... And they all add up!

Energy Expenditure Basal Metabolic Rate (BMR) The amount of energy needed to sustain life Voluntary muscle movement Calories burned in physical activity (PA) Specific Dynamic Action (SDA) of food (aka thermic affect of food) Energy required for food digestion & processing

Energy Expenditure

Basal Metabolic Rate (BMR) Energy required by the body to minimally function (heart to beat, lungs to breathe, etc) Determined in a fasting state (12 hours) and when the body is at complete rest Majority of expenditure in a sedentary person

Energy Expenditure Resting Energy Expenditure (REE) Similar to BMR Considers the amount of energy burned by a person at rest Measured in a lab or by estimated using the Mifflin equation

Mifflin Equations Based on gender, height, weight & age REE formula for women REE (Calories/ day)= (10*W) + (6.25*H) – (5*A) -161 REE formula for men REE (Calories/ day)= (10*W) + (6.25*H) – (5*A) + 5 W= Weight in Kg (pounds divided by 2.2) H = Height in centimeters (inches x 2.54) A= Age in years

Mifflin Equations Example: W= Weight in Kg (pounds divided by 2.2) H = Height in centimeters (inches x 2.54) A= Age in years Example: What is the REE for a 25 year old male who weighs 160 pounds and is 68” tall? W= 160/ 2.2= 72.72 kg H= 68 * 2.54= 172.72 cm REE= (10*W) + (6.25*H) – (5*A) + 5 REE= (727.2) + (1079.5) – (125) + 5 = 1686.7 Calories

Factors Affecting BMR/ REE Age: BMR is reduced with age Gender: More lean mass means a higher BMR (gender differences) Physiological State: Illness, pregnancy, lactation, stress & metabolic diseases like hyperthyroidism can increase the BMR. Starvation or prolonged fasting decreases BMR (up to 80% in women & 60% in men) Environmental Temperature: hot or cold temperatures increase BMR

Energy Expenditure Physical Activity (PA) Energy expended to perform physical activity Voluntary muscle movement Total amount of energy expended increases with body weight and the intensity of the exercise

Physical Activity & Calorie Burn The BMR or REE can be used to determine energy spent or Calorie burn in PA Calories burned = (Hours spent in activity x REE x Activity Factor )÷ 24 hours/day Activity Factors Sleeping/ Reclining Factor of 1 Very Light activity Factor of 1.5 Light activity Factor of 2.5 Moderate activity Factor of 5 Strenuous activity Factor of 7

Energy Expenditure Specific Dynamic Action (SDA) Food processing charge Aka thermic effect of food 10% of the total number of Calories consumed is required for the digestion, absorption & assimilation of nutrients into the body Why metabolism increases when fed

Summary Energy balance is the state of energy intake vs. energy expenditure Intake occurs with food/ beverage consumption Expenditure occurs with BMR, PA & SDA Positive energy balance = weight gain Negative energy balance = weight loss References for this presentation are the same as those for this topic found in module 3 of the textbook