Obesity is a worldwide public health problem. One in three Canadians is overweight, a prevalence that is already high and increasing. Moreover, 54% of men and 37% of Canadian women are characterized as abdominally obese, the phenotype that is strongly associated with cardiovascular disease and type II diabetes. These observations underscore the importance of considering the efficacy of methods commonly used to reduce total and abdominal obesity. These strategies include a decrease in energy intake (diet), an increase in energy expenditure (exercise), or pharmacological intervention. The combination of diet and exercise is more commonly prescribed, with pharmacological intervention suggested only when lifestyle changes fail to achieve weight loss. The aim of this report is to review current knowledge regarding the influence of diet and exercise as treatment strategies for obesity reduction and provide recommendations for attaining and maintaining a healthy weight. The importance of diet composition in the treatment of obesity is also considered.