Weight loss and its prevalence can be understood through various lenses, such as including statistics on obesity, diet trends, and health outcomes. In many countries, the prevalence of obesity has risen sharply over the past few decades. This has led to an increased focus on weight loss as a health goal for many individuals. For example, in the United States, recent data shows that over 40% of adults are classified as obese, which has significant implications for public health.
Over half of Americans are either overweight or fat, which is a big health problem in the country. Quite a few of these people are trying to lose weight. On the other hand, most people think that losing weight and keeping it off for good is hard to do. The purpose of this article is to gather all the relevant information on how to keep off the weight successfully.
How many people reach this goal? How do they do it? What is going to happen? Much of what we say about people who have successfully kept off weight comes from the National Weight Control Registry (NWCR). The information is from people who have successfully kept off the weight over the long run.
PREVALENCE OF WEIGHT LOSS MAINTENANCE
There is currently limited data on the prevalence of successful weight loss. One limitation is the lack of consistent criteria for defining “success,” and another is the difficulty in distinguishing between intentional and unintentional weight loss.
Therefore, we recommend that successful weight loss be defined as intentional weight loss of at least 10% of initial weight and maintenance of weight loss for at least one year. We did not find enough systematically collected data to provide reliable information about predictors of weight loss over longer periods.
There is generally pessimism about the long-term success of weight loss. This pessimism originated in the research of Stunkard and McLaren-Hume, who followed 100 obese subjects, referred to a nutritional weight loss program, and found that only 2% had a weight loss of at least 20 pounds 2 years after treatment. This observation has contributed to the popular media perception that almost anyone can maintain weight loss long-term.
Recent studies of clinical programs are more positive. Kramer and other scholars followed 114 men and 38 women who participated in a behavioural weight loss program annually for 4 years. By using a strict criterion of 100% weight loss maintenance, they found that only 0.9% of men and 5.3% of women were consistently successful (that means, they maintained this criterion for all 4 years). However, looking only at year 4, the cross-sectional data showed that 2.6 percent of men and 28.9 percent of women maintained 100 percent of their weight loss. Several studies have used weight loss of at least 5 kilograms as a criterion for success. According to this criterion, 13% to 22% of participants are successful 5 years after treatment.
These studies may underestimate the true prevalence of weight loss because they are based on only one period of weight loss and may not be representative of the general population. Most people who lose weight do so on their own, without participating in formal programs; thus, data from clinical trial programs may reflect “hard” diets that may be most resistant to successful weight loss maintenance.
Bartlett reviewed eight studies examining the impact of successful weight loss in community samples; they could not draw conclusions about overweight because these studies lacked consistent definitions of successful weight loss and many did not use nationally representative samples. Moreover, most studies evaluate weight loss, not maintenance.
When we look at McGuire’s study of recently reported results of a random telephone survey of a nationally representative sample of 500 adults in the United States, weight loss maintainers were defined as individuals who lost ≥ 10% maximum weight for at least 1 year during the study. Of particular interest are those who reported being overweight at their peak weight [body mass index (BMI) ≥ 27 kg/m2] (N = 228).
However, 62% of them reported that they had lost 10% of their maximum weight at some point in their lives, and 38% reported that they were currently 10% below their maximum weight. Of the 228 who reported being overweight, 69 (30.3%) maintained this 10% weight loss for at least a year. These 69 people lost an average of 42 pounds over seven years.
This study included a question about whether the weight loss was intentional. Of the 228 overweight people in the study, 47 (20.6%) reported that they had intentionally lost weight and had lost at least 10% of their weight in a year. Of these subjects, 28 fell to normal weight, as reported.
HOW TO DEFINE SUCCESS IN WEIGHT LOSS MAINTENANCE?
It is important to establish a consistent definition of successful weight loss maintenance. The definition must include criteria regarding the extent of weight loss and the duration of maintenance. Weight loss of 5-10% of initial weight can lead to significant improvements in risk factors for diabetes and heart disease and lead to reduction or discontinuation of medications for these conditions.
Thus, when the focus is on overall health, achieving and maintaining a 10% weight loss should be considered a success, although, for many obese individuals, this weight loss may not return to a non-obese state. Successful weight loss maintenance may involve some weight gain. For example, a person who lost 20% of their original weight but regained half of the lost weight would still be 10% below their original weight; their health would still be expected to improve and therefore should be considered “successful.”
When defining successful weight loss, the weight loss must be intentional. Several recent studies indicate that unintentional weight loss is common in the general population. Because the causes and consequences of unintentional weight loss are likely to be different from the causes and consequences of intentional weight loss, it is important to distinguish between the two. Finally, we propose that the minimum criterion defined by the Institute of Medicine (IOM) be 1 year of care.
A 5-year duration might be a stricter criterion, but we believe that research would be encouraged by first establishing a 1-year criterion and then examining the factors that help a 1-year achiever maintain their success over 5 years. Therefore, we recommend that individuals who intentionally lost at least 10% of their body weight and have kept it off for at least 1 year be considered “successful weight loss maintainers.” By this definition, according to the data, 21% of overweight/obese persons may be successful.
