15 Feb 2013 Researchers aim to debunk common obesity myths

Think having sex or going to gym class drives weight loss, or that breastfeeding protects a child from obesity? In fact, these are among seven popular obesity myths, according to an article published today in the New England Journal of Medicine (NEJM). Such inaccurate, widespread beliefs, the authors argue, are leading to poor policy decisions, inaccurate public health recommendations and wasted resources.

An international team of researchers led by David Allison, PhD, associate dean for science in the School of Public Health at the University of Alabama at Birmingham (UAB), analyzed articles published in the scientific and popular press to separate myths from evidence-supported facts. The authors defined myths as beliefs about obesity, many of which are fervently held despite evidence to the contrary.

“False and scientifically unsupported beliefs about obesity are pervasive,” said Allison, leader of the research team. “As health professionals, we should hold ourselves to high standards so that public health statements are based on rigorous science. In instances where the science doesn’t exist, we should conduct rigorous studies to find the answers.”

Myths about obesity

Some of the myths — beliefs commonly and fervently held (and perpetuated by both journalists and scientists), despite evidence to the contrary — include things like:

• Realistic goals are important for obesity treatment.
• Gradually losing weight is better than rapid weight loss.
• Assessing the stage-of-change or diet readiness is important in helping patients seeking weight-loss treatment.
• Being breastfed protects against future obesity.

Presumptions about obesity

Some of the presumptions — beliefs commonly held in the absence of supporting evidence — identified in the article include:

• Snacking leads to weight gain.
• Regularly eating breakfast helps prevent obesity.
• Eating more fruits and vegetables encourages weight loss.
• Yo-yo dieting leads to increased mortality rates.
• Obesity is affected by the “built environment,” things like bike paths and parks.

Facts about obesity

The study authors also listed nine facts about obesity, which include:

• Meal replacements offer an effective means of battling obesity.
• Weight-loss programs for overweight children that involve parents and the child’s home achieve better results than programs that take place solely in schools or other settings.
• Many studies show that while genetic factors play a large role in obesity, “heritability is not destiny”. Realistic changes to lifestyle and environment can, on average, bring about as much weight loss as treatment with the most effective weight-loss drugs on the market.
• Though difficult for many to sustain over the long term, eating sufficiently fewer calories effectively reduces weight.
• Exercise is useful, but only when frequent and intense enough to use up more energy than taken in, and to “a non-trivial degree”. This is only true, moreover, if one does not compensate for that exercise by increasing food intake or decreasing movement at other times.
• Pharmaceuticals can effectively promote weight reduction.
• Bariatric surgery can be an effective treatment for obesity.

University of Alabama Birmingham: Read the full article

Further reading:

For those who do not subscribe to NEJM, it can be difficult to get the full low-down on the obesity article. The abstract provides few specifics and no context, and many of the more credible news releases focus on the myths and disregard the “facts” identified by the authors.  A respectable summary of the NEJM article can be found on medpagetoday.com.

Researchers aim to debunk common obesity myths

2013; 368:446-454 DOI: 10.1056/NEJMsa1208051

“Myths, Presumptions, and Facts about Obesity”

Authors: Krista Casazza, Kevin R. Fontaine, Arne Astrup, Leann L. Birch, Andrew W. Brown, Michelle M. Bohan Brown, Nefertiti Durant, Gareth Dutton, Michael Foster, Steven B. Heymsfield, Kerry McIver, Tapan Mehta, Nir Menachemi, P.K. Newby, Russell Pate, Barbara J. Rolls, Bisakha Sen, Daniel L. Smith, Diana M. Thomas, and David B. Allison