The National Weight Control Registry
In 1994, Drs. Rena Wing, PhD, of Brown Medical School and James Hill, PhD, of the University of Colorado Health Sciences Center founded the National Weight Control Registry (NWCR) (www.nwcr.ws). To date, this project is the largest prospective investigation of long-term successful weight loss maintenance. The goal of the project was to find individuals who had been successful at weight loss and describe the strategies that they used to achieve and maintain weight loss long-term. Currently, the NWCR is tracking over 5000 individuals who have lost significant amounts of weight and kept it off for long periods of time. In order to be part of the registry, people need to be 18 years or older, who have lost at least 30 lb (6.6 kg), and to have maintained this weight loss for at least one year. Once enrolled in the program, individuals are periodically asked to fill out detailed questionnaires about their successful weight loss, current weight maintenance strategies, and other health-related behaviors for the purpose of determining the behavioral and psychological characteristics of weight maintainers, as well as the strategies they use to maintain weight loss. Participants also fill out annual follow-up surveys so that their weight maintenance can be continually tracked. Thus the NWCR is not a randomized controlled study, but rather looks at who has been successful at weight loss and at weight loss maintenance. On average, 80% of the participants are women and 20% are men who have lost 66 lb (30 kg) and kept the weight off for 5.5 years. The average woman is 45 years of age and weighs 145 lb (66 kg), and the average man is 49 years of age and weighs 190 lb (86 kg). Of course, these averages hide the huge diversity of the individuals involved in the study, as well as facts such as the following:
- Weight loss has ranged from 30 to 300 lb (13.6-136 kg).
- Duration of successful weight loss has ranged from 1 to 66 years.
- Some participants have lost the weight rapidly, while others have lost it very slowly-over as many as 14 years.
The following are strategies used by these individuals to lose weight and keep it off. Some of the information has been adapted from a review of the NWCR by Manore (2004).
Methods of weight loss. Almost everyone in the registry has used a combination of diet and exercise to lose the weight, with 45% reporting that they lost the weight on their own and 55% reporting using some type of program. Nearly all of the participants (98%) reported that they modified their food intake in some way to lose weight, while 94% said that they increased their physical activity. The most common form of physical activity reported is walking. Nearly all of the participants have reported that their weight loss has led to significant improvements in energy levels, physical mobility, general mood, self-confidence, and physical health (Klem et al. 1997). Participants (~42%) state that keeping the weight off has not been as difficult as losing it initially (Klem et al. 1997). This is especially true in individuals who have kept the weight off for more than two years (Klem et al. 2000).
Strategies for weight maintenance. Since the initiation of the NWCR, investigators have been analyzing the data to determine successful weight maintenance strategies (Gorin et al. 2004; Hill and Wing 2003; Klem et al. 1997; McGuire et al. 1998; Phelan et al. 2007; Raynor et al. 2006; Shick et al. 1998; Wyatt et al. 2002). In general, most participants report continuing to maintain a low-calorie, low-fat diet and doing high levels of physical activity. The following are some of the specific and most frequently mentioned strategies used by participants who have been successful at maintaining weight loss:
- Eating breakfast. Nearly 80% of participants report eating breakfast every day, with only 4% reporting never eating breakfast. How might eating breakfast contribute to successful weight maintenance? Although there were no differences in total energy intake between frequent breakfast eaters and less frequent breakfast eaters (three times a week or less), breakfast eaters reported being more physically active (Wyatt et al. 2002).
- Monitoring energy and fat intake. A common characteristic of registry participants is that they continue to monitor their energy and fat intake even after the weight loss period is over. On average, participants consume diets with ~24% of energy from fat and have energy intakes lower than average (Shick et al. 1998). As a group, 80% consume diets with <30% of energy from fat, while 35% consume diets with less than 20% of energy from fat. The strategies employed to control food intake include limiting intake of certain high-fat foods, eating less food per meal, counting grams of fat or calories, eating regular meals, and adhering to the same diet regimen throughout the week (Klem et al. 1997; Gorin et al. 2004). Diet consistency across the week appears to help people prevent weight gain (Gorin et al. 2004).
- Exercising daily. Being physical active is an important characteristic of registry participants, with 90% reporting that they exercise, on average, about 1 h or more per day. Weekly energy expenditures from physical activity average ~2800 kcal: ~2500 kcal/week for women and 3300 kcal/week for men (Hill and Wing 2003; Klem et al. 1997). The most common forms of physical activity reported are cycling, aerobics, walking, and running (Klem et al. 1997). Comparison of the levels of physical activity between successful weight loss maintainers and people who had always maintained a normal weight showed that the weight loss maintainers spent significantly more time in high-intensity forms of physical activity and spent more minutes per week doing physical activity (Phelan et al. 2007).
- Engaging in less sedentary activity. It has long been recognized that sedentary behaviors, especially TV viewing, may contribute to weight gain. Raynor and colleagues (2006) examined the TV viewing of registry participants and found that 62% watched <10 h of TV per week, with 36% reporting that they watched <5 h/week. This level of TV viewing is much lower than the national average of 28 h/week.
- Monitoring weight. Nearly 75% of the registry participants weigh themselves at least once a week (Klem et al. 1997). Thus, regularly monitoring weight appears to be a behavior that is important for ensuring that weight regain does not occur.
What we have learned from the participants in the NWCR is that good nutrition, physical activity, and self-monitoring are important for keeping the weight off once it has been lost. Individuals who are successful at weight loss and the maintenance of weight loss appear to employ similar strategies. They eat breakfast, exercise regularly, monitor their diet for both energy and fat intake, participate in less TV watching, and weigh themselves regularly.