The Body’s Energy Balance

The Body’s Energy Balance NOTE: This topic has a three-part lecture. View each lecture and complete the guided notes. Part 1: Macronutrients Distribution (calorie) calculations a) Calorie Calculations The energy value of food can be calculated if you know the number of grams of carbohydrate, protein, fat and alcohol. How many Calories are in soup with the following contents? Carbohydrates 15g Protein 10g Fat 5g Alcohol 0g - Calculate the number of calories the food provides based on the number of grams per nutrients that a food has and if it has any alcohol (add kcal’s). There is no Alcohol in this soup. There are 4 kcal in every gram of carbohydrates, 4 kcal in every gram of protein, and 9 kcal in every gram of fat. Thus: Carbohydrates = 15 g x 4 kcal/g = 60 kcal = 41% of energy provided Page 8 Unit 3— Body Weight and Health Protein = 10 g x 4 kcal/g = 40 kcal = 28% of energy provided Protein = 10 g x 4 kcal/g = 40 kcal = 28% of energy provided Fat = 5 g x 9 kcal/g = 45 kcal = 31% of energy provided Alcohol = 0 g x 7 kcal/g = 0 kcal = 0% of energy provided TOTAL = 145 kcal (caloric content) in the soup Carbohydrate 60 kcal of carbohydrates 145 kcal Total = 0.41 = 41% Protein 40 kcal of carbohydrates 145 kcal Total = 0.28 = 28% Fat 45 kcal of carbohydrates 145 kcal Total = 0.31 = 31% Note: The combined percentages of energy from the macronutrients is 100% (41%+28%+31%= 100%) b) Summary - Energy values of food can be calculated from the amounts of carbohydrates, fat and protein, and alcohol (if present) in the foods. - The energy derived from the macronutrients and alcohol is expressed as kilocalories or kcals. Also known as Calories. 1g of carbohydrate has 4 kcal, 1g of protein has 4 kcal, 1 g of fat has 9 kcal and a gram of alcohol has 7 kcal. Part 2: Energy Intake versus Energy Expenditure a) Calories Calories - a measurement for energy contained in food. The energy value of a food is expressed in the number of calories it provides. - A food’s kilocalorie value is determined by the amount of heat released and transferred to water when the food is completely burned. - 1,000 calories (lower case c) = 1 kilocalorie (kcal) Calorie and kilocalorie (kcal) are interchangeable in common speech A Calorie (kcal) is the amount of energy needed to raise the temperature of 1kg of water from 150C to 160C Scientists measure the amount of heat given off (calories) when food is burned inside a bomb calorimeter. b) The Body's Energy Balance The body’s energy balance is the difference between energy intake (energy in) compared with energy expenditure (calories you spend to maintain your body). - Change in energy stores occur when “energy in” is different than “energy out.” - Discrepancies between these two then produce either weight gain or weight loss. - In a negative energy balance our energy intake is less than our energy need producing weight loss. - In North America, energy intake is typically higher than energy need weight gain. - Weight maintenance is balanced when your intake equals your need. - A balanced system is required to achieve the goal of weight maintenance. If you want to eat more, you have to put out more energy. c) Energy Balance Calculations - 1 lb body weight = 3 500kcal - Energy intake – Energy need (EER) =kilocaloriekilocalorie difference. 1. Weight gain example Energy intake – Energy need (EER) = kcal difference 3000 kcal - 2000 kcal = 1000 kcal/day Introduction to Unit 4 – Macronutrients and Health Macronutrients are nutrients required by the human body in large quantities. Macronutrients are the only essential nutrients that provide energy for the human body. When quality macronutrients are consumed in optimal quantities, the result is optimal health. Unfortunately, when macronutrients are consumed in excess, in deficit or poor quality choices are made, the result is often the development of chronic disease. Lessons in this unit will provide knowledge for identifying optimal macronutrient choices and the health implications of macronutrients consumed outside of the healthy range.