Energy Extension

Learning Goals I will be able to describe strategies to balance the body's energy intake and output. I will be able to calculate and understand my own BMR and BMI I will be able to explain various factors that affect the body's use of energy.

What is energy? Energy is the power used to do work or to produce heat or light. Energy cannot be created or destroyed, but can be changed from one form to another. It is measured in kilojoules (kJ) or megajoules (MJ). When using imperial measurements, kilocalories (kcal) are used. 1kJ = 1000J 1MJ = 1000kJ 1kcal = 1000cal 1kcal = 4.18kJ

Energy from food When we consume food and drink, energy provided by carbohydrate, protein, and fat (and alcohol) is metabolised and used by our bodies. Carbohydrate, protein, and fat (and alcohol) are broken down into smaller compounds which are then oxidised in the cells of the body (respiration).

Energy Balance

Energy intakes Experts have estimated the average requirements for energy for different types of people. These figures are known as Estimated Average Requirements (EAR) for energy. Experts also recommended that: • about 50% of our energy intake should come from carbohydrate; • no more than 35% of our energy intake should come from fat; • about 15% of our energy intake should come from protein.

Energy expenditure Different people need different amounts of energy, depending on a variety of factors, including their: basal metabolic rate (BMR); level of physical activity; age; sex; body size.

Basal metabolic rate The basal metabolic rate (BMR) is the rate at which a person uses energy to maintain the basic functions of the body e.g. breathing. BMR is measured when a person is at complete rest, and varies between person to person. Men usually have a higher BMR than women because they tend to have a larger muscle mass. The BMR accounts for 75% of an individual’s energy needs.

Energy balance To maintain body weight it is necessary to balance the energy derived from food with that expended in activity. Energy balance is achieved when energy intake equals energy expenditure. The total amount of energy required by an individual depends on their level of activity. The more active an individual is, the more energy they need.

Positive energy balance When the diet provides more energy than is needed, it is stored as fat and the person puts on weight over time. People who are in positive energy balance over an extended period of time (i.e. they take in more energy than they use) are likely to become overweight or obese.

Overweight and obese Excess energy is stored in adipose tissue and can build up if energy intake continues to be too high, or activity levels remain too low. Being overweight or obese is associated with an increased risk of developing certain cancers, cardiovascular disease and type 2 diabetes.

Negative energy balance A person is said to be in negative energy balance when there is insufficient energy from the diet to meet energy demands of the body. Energy is derived from energy stores and the person looses weight. People who achieve a negative energy balance over an extended period of time, are likely to become underweight.

Underweight When too little energy is consumed over a period of time, the body derives energy from fat stores leading to weight loss. When too much fat is lost, the person becomes underweight. Being underweight is associated with health problems, such as osteoporosis, infertility and heart failure.

Energy Expenditure

Components of Energy Expenditure

Running~14.1 kcal/min @ 7.5 mph

Monitoring energy balance For adults, change in weight is a good guide to energy balance. The Body Mass Index (BMI) is a good indicator of whether a person is underweight, overweight or a healthy weight. The BMI range should only be used for people aged 18 years of age and over. We are all encouraged to maintain a healthy weight by balancing energy intake with energy expenditure.

Calculating BMI kg . m2 Step 1 Height in meters (m) x height in metres (m) Step 2 Divide weight in kilograms (kg) by step 1 Step 3 Equals BMI. Next refer to guide below. OR go the the website http://bmicalculator.cc/ Recommended BMI range Underweight less than 18.5 Normal 18.5 - less than 25 Overweight 25 - less than 30 Obese 30 - 40 Very obese over 40

Calculating BMI kg . BMI = m2 Calculate these 3 examples: 1. Samantha Height: 1.70m Weight: 51kg 2. Dale Height: 1.95m Weight: 82kg 3. Ruth Height: 1.63m Weight: 78kg Recommended BMI range Underweight less than 18.5 Normal 18.5 - less than 25 Overweight 25 - less than 30 Obese 30 - 40 Very obese over 40 kg . m2 BMI =

BMI example 1 51kg . 1.7m x 1.7m BMI = 17.6 Samantha Height: 1.70m Weight: 51kg 51kg . 1.7m x 1.7m BMI = 17.6 Samantha is underweight. Recommended BMI range Underweight less than 18.5 Normal 18.5 - less than 25 Overweight 25 - less than 30 Obese 30 - 40 Very obese over 40

BMI example 2 82kg . 1.95m x 1.95m BMI = 21.6 Dale Height: 1.95m Weight: 82kg 82kg . 1.95m x 1.95m BMI = 21.6 Dale is a healthy weight. Recommended BMI range Underweight less than 18.5 Normal 18.5 - less than 25 Overweight 25- less than 30 Obese 30- 40 Very obese over 40

BMI example 3 78kg . 1.63m x 1.63m BMI = 29.4 Ruth Height: 1.63m Weight: 78kg 78kg . 1.63m x 1.63m BMI = 29.4 Ruth is overweight. Recommended BMI range Underweight less than 18.5 Normal 18.5 - less than 25 Overweight 25- less than 30 Obese 30- 40 Very obese over 40

Basal Metabolic Rate (BMR) Is basically a calculation that tells you the basic amount of energy that you are expending doing no activity (basically if you lied in bed all day how many calories you would expend) The BMR is based on your height, weight, age and sex Go to the link below to calculate your BMR http://www.bmi-calculator.net/bmr-calculator/

Once you have your BMR…. Click on Daily Calorie Needs link below. Time for some math!! To figure out how many calories you need you need to use the Harris- Benedict method to decide how active you are. Based on the calculation how many calories do you need to MAINTAIN your current weight?

Your Turn! So now you know how to read food labels and how many calories you need in a day to maintain your current weight. The Task: It’s a big one! Your task is to create a one day meal plan When planning your meal plan you must complete the following criteria It must have enough calories to MAINTAIN your current weight You must consume enough daily servings sizes according to Canada’s food guide You must get the required amount of Micro nutrients according to the Daily Values on labels