Energy Balance

Energy balance occurs when the amount of energy we eat ("Energy In") is equal to the amount of energy our bodies use ("Energy Out"), resulting in the maintenance of body weight. "Energy In" is the energy (calories) we get from the carbohydrate, fat, and protein in food. "Energy Out" is the energy needed to perform basic body functions like breathing and keeping the heart beating, digesting and processing food, and to fuel voluntary activities like walking, talking, or playing basketball. In children, pregnant and lactating women, more food energy is needed for growth and development.

Energy In: Typical Breakdown of Caloric Intake
protein 0.15
fat 0.3
carbohydrate 0.55
Energy Out: How Calories are Used
physical activity 0.30
digesting food 0.1
basic body functions 0.6

Weight gain results when "Energy In" from all food sources and beverages is greater than "Energy Out" from physical activity and other body functions. This is known as positive energy balance. Continued positive energy balance over time can eventually lead to becoming overweight or obese. These conditions of excess body fat are associated with health problems, including heart disease, stroke, diabetes, and cancer.

A "negative energy balance" is necessary to lose weight. This requires a decrease in energy intake from foods and/or an increase in energy output. The amount of energy used for basic body functions depends largely on genetic factors like age, gender, and body size so it is hard to change. We can however, modify food intake and physical activity to maintain energy balance or to achieve negative energy balance.

Aiming to adopt a healthy lifestyle can help to ensure energy balance and a healthy body weight. Following  Eating Well with Canada’s Food Guide and  Canadian Physical Activity Guidelines will help you to achieve the many long term health benefits of a healthy lifestyle.

For more information on Weight Management, please refer to CSI resource  Clips on Sugars - Balancing Food and Activity for Healthy Weights

Healthy Eating

Healthy eating is defined by the sum total of all food choices made over time. The overall pattern of food choices, rather than one particular food or meal consumed in a day, determines whether a pattern of eating is healthy.  Eating Well with Canada's Food Guide adopts this approach to healthy eating (termed a "total diet approach") and is designed to guide consumers who have a wide range of energy needs, in the selection of all foods.

The food we eat is a complex mixture of different components. The most important ones are carbohydrate, protein, fat, fibre, vitamins, minerals, and water. Of these, only carbohydrate, protein, and fat provide energy. Each gram of carbohydrate (sugars and starches) and protein provides 4 Calories, while fat supplies 9 Calories per gram. Fibre also contributes 2 Calories per gram. However, only carbohydrate (sugars, starches, fibre), found predominantly in grains (e.g., cereals, breads, pasta), fruits, and vegetables, is ultimately converted by the digestive system into glucose, the "official" fuel of the human body. In order to function, each human cell needs fuel and the preferred fuel for the body is glucose. As cells never stop working, glucose must always be available.

In Canada, current dietary guidance for adults and children states that most of our daily energy (45 - 65% of our total Calories) should come from carbohydrate (sugars, starches and fibre) and the remaining from fat (20-35%) and protein (10-35%). This recommendation is based on the Dietary Reference Intakes (DRIs), a set of nutrient intake standards for healthy people, established by the US Institute of Medicine in collaboration with Health Canada. The DRIs reflect the current state of scientific knowledge with respect to nutrient needs. According to Canadian Community Health Survey data, 32% of adult males and 24% of adult females have carbohydrate intakes below the dietary recommendations. 

Carbohydrate should come from a variety of sources such as whole grain products, vegetables, and fruit, for a healthy, balanced diet. Sugars (such as those added to breakfast cereals, sweetened yogurts, jams, jellies, and syrups) add taste and enjoyment to foods and also contribute to carbohydrate intake.

For more information on dietary guidance in Canada, please visit  Health Canada

Click here (pdf) for student activities and experiments related to Energy Balance and Food Energy

Physical Activity 

Benefits of Physical Activity

Participating in regular physical activity can help manage body weight and reduce the risk of developing chronic diseases like heart disease and diabetes. Physical activity also improves sleep and can reduce stress, anxiety, and depression. For young Canadians, physical activity encourages optimal growth and development and can help build positive self-esteem. For older Canadians, physical activity can help individuals to continue living independently and improve quality of life.

Physical activity also has economic and environmental benefits, including reduced health care costs and increased productivity from fewer lost work days from injury and sickness. Being physically active can also help reduce air pollution and traffic congestion by walking or riding a bike instead of driving.

Physical Activity Recommendations

With support from the Public Health Agency of Canada, the Canadian Society for Exercise Physiology (CSEP) released updated physical activity guidelines for Canadians in 2011. The Canadian Physical Activity Guidelines are designed to help promote physically active lifestyles in order to improve health, increase vigour, prevent disease, and get the most out of life at various life stages: 

The Physical Activity Guidelines encourage individuals to participate in a variety of forms of exercise (e.g. aerobic, strengthening) to achieve health benefits and recommend limiting recreational screen time to no more than 2 hours per day and to limit sedentary transport, extended sitting, and time spent indoors. Below are examples of different types of activities of varying intensities to support active living:

Type of exercise Intensity Time needed daily for adults Examples
Moderate intensity Will cause you to sweat a little and to breathe harder Bouts of 10 minutes or more, to contribute to 60 minutes of daily physical activity Brisk walking, biking, swimming, dancing, etc.
Vigorous intensity Will cause you to sweat and be ‘out of breath’ Bouts of 10 minutes or more, to contribute to 60 minutes of daily physical activity Aerobics, jogging, basketball, fast dancing, etc.

Physical activity is not just about exercise programs and sports. It is important to do activities that feel good and are fun. The goal isn’t just to burn calories, but to enjoy the feeling of movement and to make it part of everyday life, whether it’s taking the dog for a walk, flying a kite, or dancing to your favourite music. Active living encourages everyone, not just people who are young and fit, to get up and moving!

For more information on physical activity, please refer to CSI resource  Clips on Sugars - Balancing Food and Activity for Healthy Weights.