NEJM takes on weight loss myths

By Katie Fesler

There is a set of beliefs around the origin, nature, and treatment of obesity and weight loss that guides the thinking, research, policy making, and counseling of both nutrition professionals and the public. These pervasive beliefs are generally accepted as evidence-based.  But do they hold up under scrutiny? Is there truly enough research behind these claims to permit them to infiltrate all aspects of nutrition? An article published this January in the New England Journal of Medicine (NEJM) explores this question.

The NEJM article examined seven myths and six presumptions. Myths were classified as having evidence against them; presumptions were considered those beliefs that do not have enough evidence to say whether they were true or false. So what are these myths? Could their lack of support have implications? We will examine the first six myths presented.

Source: Fox News

Source: Fox News

Myth #1: “Small sustained changes in energy intake or expenditure will produce large, long-term weight changes”

Yes, it is true that exercising to burn more calories (if not negated by increased calorie intake) will lead to weight loss. It is also true that there is a benefit from sustaining these changes. The issue is how health guidelines and popular websites and magazines interpret this myth. These sources lead individuals to believe that a small change will have indefinite impact on weight. However, a small, sustained change will ultimately max out its impact. You will not continue to progressively lose weight because of decreases in energy requirements.

Does that mean this myth can be ignored? Should those small changes be abandoned once you stop losing weight? Absolutely not! This is where the sustained change comes in. It is still important that these small changes are permanent changes to help ensure that the weight that came off, stays off.

Myth #2: “Setting realistic goals for weight loss is important, because otherwise patients will become frustrated and lose less weight.”

The article calls this statement a myth because the literature search did not find significant evidence that realistic goals are more successful than large goals. In fact, it found evidence that large goals are more successful for some. So where did this myth come from?

It is based on the goal-setting theory that states, “unattainable goals impair performance and discourage goal-attaining behavior.” For many, this myth still holds. However, it is important to realize that not all people will respond best to small goals; some need larger goals to strive for. This myth is a reminder that each patient, and situation, is different.

Myth #3: “Large, rapid weight loss is associated with poorer long-term weight-loss outcomes, as compared with slow, gradual weight loss.”

With this myth, there is evidence to support both sides. For some, rapid weight-loss at the beginning results in greater success. For others, smaller weight loss at the beginning proved more successful. So why is this one called a myth? The authors argue that recommending only slow weight-loss may interfere with the success of weight-loss efforts – especially if the individual is more likely to be successful with a strong start.

On the other, recommending large weight loss can be dangerous if not carefully moderated. It is important that if rapid weight loss is recommended, people do not attempt to achieve this with a very low calorie diet.

Myth #4: “It is important to assess the stage of change or diet readiness in order to help patients who request weight loss treatment.”

Number 4 reflects the belief that only when patients feel ready to lose weight are they likely to make the required lifestyle changes. It is not an unrealistic claim. However, there are trials that specifically examined varying magnitudes of weight-loss success based on how ready the patient was to make changes. They found little difference among participants. Keeping this in mind, it should not dispel the idea that patients need to be ready to make changes for successful weight-loss. The article points out that it is likely that those willing to sign up for a weight loss program are ready to make changes.

So if people in a weight loss program are going to be ready anyways, what is the harm of this myth? The issue is that this myth encourages the practitioner to make a judgment about the patient’s readiness. They may inaccurately believe that the patient is not ready and alter the course of action, harming the patient’s success. Additionally, more effort may be spent evaluating a person’s readiness to change rather than on the intervention.

Myth #5: “Physical-education classes, in their current form, play an important role in preventing childhood obesity.”

This myth is already on its way towards being unraveled. Research shows that even with increased time spent in physical education, children’s BMIs do not significantly change. The frequency, intensity, or duration of activity must increase for there to be an impact from these classes. More research is being done to determine what that level of activity is and how it can become part of the physical education classes.

Myth #6: “Breast-feeding is protective against obesity.”

This belief has been around for an extensive amount of time. However, upon investigating, the article reports that there are more studies that show breast-feeding does not have a protective effect against obesity than studies showing that it does. The tricky part is that correcting this myth can have larger negative effects than allowing it to persist. The fact that breast-feeding may not have a protective effect against obesity does not mean the other benefits are also not true. Breast-feeding is still beneficial to both mom and baby. Discussions of the connection to obesity must be careful to get the message across that breast-feeding is still a beneficial, and recommended, practice.

While these myths may not be entirely true as stated, there are truthful aspects to them and each must be considered in context. As always, it is important to remember that new research is published continuously. What is considered a myth today may have scientific backing tomorrow. This article reminds us to keep up with and critically access the research. It is a reminder to be willing to change our way of thinking if sufficient research directs us to do so.

Katie Fesler is a first-year Nutrition Communications student.

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