On any given day, at least one out of every four North Americans is on a diet. In North American, we spend more than $30 billion annually on various weight-loss methods, most of which fail. Excess body weight is associated with numerous health-related problems including increased risk for coronary artery disease, diabetes, and high cholesterol. Osteoarthritis of the knee is also more common in those who are overweight. Unfortunately, 95 percent of people who lose weight are unsuccessful at keeping the weight off. Moreover, an obsession with weight and weight loss can lead to eating disorders such as anorexia and bulimia, which are serious medical and mental health conditions.
Have you ever wondered how some people who lose large amounts of weight mange to keep it off over the long term, while others regain it easily? So have Dr. James O. Hill, PhD and Dr. Rena Wing, PhD, researchers from University of Colorado and Brown University, who established the National Weight Control Registry (NWCR) in 1994. The objective of the NWCR is to study the behaviour and psychology of individuals who are weight maintainers – that is, those who have lost weight and kept it off for an extended period of time. By gaining insight into how they do it, those who struggle with weight management can adopt strategies that are known to set most people up for success. These are the finding thus far from the Registry:
- 80 percent of the participants are women, and 20 percent are men.
- The average woman is 45 and currently weighs 145 lbs, and the average man is 49 and currently weighs 190 lbs.
- Registry members have lost an average of 66 lbs and kept if off for 5.5 years. However, weight losses have ranged from 30 to 300 lbs, and duration of successful weight loss has ranged from 1 to 66 years!
- Forty-five percent of participants have lost the weight independently, while the other 55 percent have used a program.
- Ninety-eight percent of participants modified their food intake in some way to lose weight, primarily to a low-fat, lower-calorie diet.
- Ninety-four percent increased their physical activity, with walking the most common form of activity reported.
- Most eat breakfast every day.
- Most weigh themselves at least once a week.
- Sixty-two percent watch less than ten hours of tv per week.
- Ninety percent exercise, on average, about one hour each day.
I would also add that basal metabolic rate decreases as one ages, so one's caloric intake needs to decrease with age, or weight gain will occur. For some, metabolism slows down to such an extent that the required caloric intake is a fraction of what it was a younger age. This can be a cruel awakening, and difficult to deal with in a food-centric culture. That being said, those who continue to eat as they always did will invariably gain weight over time, some more than others. When it comes to weight gain, most people gain several pounds a year - not a large amount of weight at once. Therefore, weight gain over time tends to be insidious.
The Bottom Line:
Successful weight loss must involve a combination of dietary modification and regular exercise. The evidence to date suggests that exercise alone is usually not sufficient to elicit weight loss. Exercise volume must be sufficiently high – what we have learned from the NWCR is that an hour a day of moderate- or high-intensity exercise is ideal. In addition, self-monitoring is crucial to long-term success. Lastly, eat breakfast and don’t watch too much tv! A recent study found that people who lose weight and keep it off have fewer household televisions (I wonder how the NWCR is adressing other screens in their studies!).
- American Council on Exercise (2003). Personal Trainer Manual. San Diego: American Council on Exercise.
- National Weight Control Registry website, www.nwcr.ws
- Gorin, A. et al. (2010). Decreasing household television time: A pilot study of combined behavioural and environmental intervention. Behavioral Interventions, 21(4), pp. 273-280.