Overweight and Obesity

What causes weight gain?

There is no single cause of weight gain, but many different risk factors such as genetics, dietary habits, level of physical activity, gut (microflora) health, environmental factors, sleep patterns, and mental stress. The amount of body fat and its distribution in the body (especially around the abdominal area) are more accurate indicators of obesity rather than body weight alone.

An individual may be at an increased risk of becoming overweight or obese when more energy (calories) is eaten from all foods and beverages than is used for normal bodily functions (e.g., breathing, digestion, pumping blood), daily movement, and physical activity. Protein, carbohydrate (e.g. sugars, starches), fat, and alcohol from all food and beverage sources contribute calories, which can be converted into body fat if consumed in greater amounts than needed by the body. Fluctuations in energy balance (higher or lower energy intake relative to use) within a meal, day or week are normal and will not necessarily lead to a persistent change in body fat. However, increases in energy intake relative to expenditure (i.e., positive energy balance) over a long period of time may increase the likelihood of the unused calories being stored as fat in the body. 

It is important to remember that neither excess calorie intake, poor food choices or eating habits is the sole cause for weight gain given the number of factors involved. 

To learn more, visit our webpage: Sugars and Overweight and Obesity, or download our infographic: Energy Balance and Body Weight

What is the best way to lose weight?

From a diet perspective, talking to a registered dietitian may help in adopting a healthier eating pattern that can be sustained. A healthy eating pattern is one that has the right amount of Calories from a balanced ratio of carbohydrates, fats, and proteins, as well as enough of the essential vitamins, minerals, fibre and other nutrients our bodies need.

It is quite difficult to lose weight only by “eating less calories” because of the strong biological mechanisms in the body to act against weight loss, as well as other environmental and social factors associated with weight. Getting enough sleep and incorporating physical activity into daily routines can also help maintain a healthy weight. Follow the Canadian 24-hour Movement Guidelines to achieve a balanced lifestyle for physical activity, sedentary behaviour, and sleep.

Some suggestions related to diet include: 

  • Selecting nutrient-dense whole foods more often, including whole fruits and vegetables, whole grains, legumes, and lean meats.
  • Moderating portion sizes and/or frequency of higher calorie snacks. 
  • Choosing water as a zero-calorie beverage to quench thirst most often.
    • Enjoying sugar-sweetened beverages occasionally. 
    • Choosing plain coffee or tea and adding milk and/or a small amount of sugar to suit individual tastes rather than ordering pre-prepared coffee and tea-based beverages.

To learn more about sugars and weight, visit our webpage Sugars and Overweight and Obesity, or download our resources: