Dietary, Behavioral, and Physical Activity Recommendations for Weight Management

We have just considered the gravity of the obesity problem in North America and worldwide. Successful weight loss is defined as individuals intentionally losing at least 10 percent of their body weight and keeping it off for at least one year.^[1] Results from lifestyle intervention studies suggest fewer than 20 percent of participants are successful at weight loss. An evaluation of successful weight loss, involving more than fourteen thousand participants published in the November 2011 issue of the International Journal of Obesity estimates that more than one in six Americans (17 percent) who were overweight or obese were successful in achieving long-term weight loss.^[2] However, these numbers are on the high end because many similar studies report fewer than 10 percent of participants as successful in weight loss.

A study tracking over ten thousand people who have been successful in losing at least 30 pounds and maintaining this weight loss for at least one year found that 98 percent of participants in the registry modified their food intake and 94 percent increased their physical activity (mainly walking).^[3] Although there are a great variety of approaches taken by the participants to achieve successful weight loss, most report that their approach involved adhering to a low-calorie, low-fat diet and doing high levels of activity (about one hour of exercise per day). Moreover, most members eat breakfast every day, watch fewer than ten hours of television per week, and weigh themselves at least once per week. About half of them lost weight on their own, and the other half used some type of weight-loss program. In most scientific studies successful weight loss is accomplished only by changing the diet and by increasing physical activity. Doing one without the other limits the amount of weight lost and the length of time that weight loss is sustained. On an individual level it is quite possible to achieve successful weight loss. Moreover, losing as little as 10 percent of your body weight can significantly improve health and reduce disease risk.^[4]

You do not have to be overweight or obese to reap benefits from eating a healthier diet and increasing physical activity as both provide numerous benefits beyond weight loss and maintenance.

Evidence-Based Dietary Recommendations

Canada’s Food Guide offers specific, evidence-based recommendations for dietary changes aimed at keeping calorie intake in balance with physical activity, which is key for weight management. These recommendations include:

Follow a healthy eating pattern that accounts for all foods and beverages within an appropriate calorie level that includes:

• A variety of vegetables from all of the subgroups—dark green, red and orange, legumes (beans and peas), starchy, and other
• Fruits, especially whole fruits
• Grains, at least half of which are whole grains
• Fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages
• A variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products
• Oils

A healthy eating pattern limits:

• Saturated fats and trans fats
• Added sugars
• Sodium

Evidence-Based Physical Activity Recommendations

The other part of the energy balance equation is physical activity. The Canadian Society for Exercise Physiology (CSEP) in partnership with Participaction have developed physical activity guidelines for Canadians of all ages. The recommendations for adults (18-64 years of age) include 150 minutes of moderate to vigourous-intensity aerobic physical activity per week in bouts of 10 minutes of more. It is also beneficial to add strength training activities 2 days per week. ^[5] Increased physical activity has been found in scientific studies to lower the risk of heart disease, stroke, high blood pressure, Type 2 diabetes, colon, breast, and lung cancer, falls and fractures, depression, and early death. Increased physical activity not only reduces disease risk, but also improves overall health by increasing cardiovascular and muscular fitness, increasing bone density and strength, improving cognitive function, and assisting in weight loss and weight maintenance.^[6]

The key guidelines for adults are the following (those for pregnant women, children, and older people will be given in Chapter 13):

• Even small amounts of activity are beneficial to your health.
• More substantial health benefits are obtained by doing at least two hours and thirty minutes per week of moderate-intensity, or one hour and fifteen minutes per week of vigorous-intensity aerobic physical activity, or an equivalent combination thereof. Aerobic activity has better benefits if performed for at least ten minutes at a time, spread throughout the week.
• More extensive health benefits occur when moderate-intensity physical activity is increased to five hours per week, or to two hours and thirty minutes of vigorous-intensity aerobic physical activity, or a combination thereof. Additional health benefits are gained by going beyond these recommended amounts of physical activity.
• Muscle-strengthening activities at moderate or high intensity involving all major muscle groups two or more days per week provides additional health benefits to aerobic exercise.

Moderate physical activities are described as those when “you can talk while you do them, but can’t sing” and vigorous activities as those when “you can only say a few words without stopping to catch your breath.”^[7]

Table 8.7 Moderate and Vigorous Physical Activities^[8]

The “Small-Change” Approach

Scientific studies have demonstrated that asking people to increase the number of steps they take each day while providing them with pedometers that count the steps they take each day successfully prevented weight gain. A “small-changes” study published in the October 2007 issue of Pediatrics evaluated whether families that made two small lifestyle changes, which were to walk an additional two thousand steps per day and to eliminate 100 kilocalories per day from their typical diet by replacing dietary sugar with a noncaloric sweetener, would prevent weight gain in overweight children.^[9] The results of this study were that a higher percentage of children who made the small changes maintained or reduced their BMI in comparison to children of families given a pedometer but not asked to also make physical activity or dietary changes.^[10] Several more studies are ongoing and are evaluating the effectiveness of the “small-changes” approach in reducing weight gain.