Energy Balance

Energy Balance : 

Energy Balance Getting the Equation to Work

The Hard Question : 

The Hard Question How much should I eat each day? What you are doing Positive/negative or equal energy balance Need to calculate BMR

Each Person is an Individual : 

Nutrition Applied PT571001; SP572001; SM569001 Each Person is an Individual Largest energy requirements for those who are: Young Growing Large Muscular Have long high intensity training sessions

Energy Balance : 

Energy Balance Total Daily Energy Intake: (TDEI) refers to the energy obtained from the diet in a day period Total Daily Energy Expenditure: (TDEE) refers to all the energy used to power the body through a day period Energy Balance when: TDEI = TDEE → amount of energy put into body equals amount of energy spent over the day.

Energy Balance and Body Weight : 

Energy Balance and Body Weight If TDEI = TDEE body weight (BW) remains stable If TDEI > TDEE POSITIVE energy balance body stores extra energy ( BW) If TDEI < TDEE NEGATIVE energy balance body uses stored energy to make up difference ( BW) Changing energy balance affects body weight

How Do We Measure Energy Expenditure? : 

How Do We Measure Energy Expenditure? Indirect Calorimetry Hard to do in the field Measures RER by O2/CO2 ratios Reliant on knowing diet and exercise Doubly-labelled Water Accurate but very expensive Prediction Equations

Food Energy : 

Food Energy The macronutrients in food provide energy to power body functions. Food energy measured in kilojoules (kJ) or kilocalories (kcal or Cal): 1Cal = 4.2kJ What you eat is important because: Different energy kJ/g of each nutrient: CHO = 16kJ/g Protein = 17kJ/g Fat = 37kJ/g Alcohol = 29kJ/g Nutrients used differently in the body

Food Energy : 

Food Energy Alcoholin = Alcoholoxidation Carbohydratein = Carbohydrateoxidation Fatin = Fatoxidation Proteinin = Proteinoxidation When any of the nutrients in are greater than the oxidation then have food energy stored.

Total Daily Energy Expenditure : 

Total Daily Energy Expenditure How do we change our TDEE? BMR Physical Activity Thermic Effect of Food

What is TDEE : 

What is TDEE The energy used to power the body through 24 hours TDEE is made up to 3 parts: Basal Metabolic Rate (BMR) Energy required for basic body functions 50-60% TDEE Physical Activity Includes energy cost of purposeful activities of daily living and/or planned exercise 20-40% TDEE Thermic Effect of Food (TEF) Energy required to process food in the body <10% TDEE

Basal Metabolic Rate : 

Basal Metabolic Rate Basal metabolic rate influenced by: Body Size: BMR  with body mass Body Composition: adipose (fat) tissue has lower energy demand than muscle → BMR  with  muscle;  with  fat. Age: BMR  with age Gender: BMR  women cf men ( total mass, women higher fat to muscle ratio) Genetic component Nutritional status: adaptive changes to modified energy intake

Physical Activity : 

Physical Activity Most variable component of energy expenditure. Physical activity energy demand influenced by: Type ( with  weight bearing/loading) Intensity ( with  intensity) Duration ( with  duration) Size of Individual ( with  size) Rest between movements ( with  rest) Skill of movement (muscle efficiency) ( with  skill)

Factors Affecting TEF : 

Factors Affecting TEF Genetically determined?? Diet composition:  TEF in response to protein cf fat and CHO Very small contributor to total daily energy expenditure