This is a short list of a few of my favorite studies that support the Health At Every Size (HAES) movement. Of course, a whole host of studies exist supporting HAES, but I chose these five because they touch on a variety of key points and common misconceptions – and are interesting to read. Only one of these studies was actually written from a weight neutral perspective; the rest are from a weight focused approach but nonetheless have findings that support the HAES theory. It is important to note that some of these authors use language that could be triggering, and/or discuss unhelpful judgments from a weight normative perspective in the introduction or discussion sections. Nonetheless, these studies have contributed to the body of evidence in support of HAES and are important ones to know about!
In our culture, a fear of fatness (fatphobia) leads to many false assumptions. One common one is that increased fatness causes a shorter lifespan. This meta-analysis looked at deaths associated with the full spectrum of weights, in older adults specifically. The lowest rates of death were associated with a BMI range from 25-35 (see graph below). Note that in our health care system, a BMI of over 25 is considered “overweight” and over 30 is deemed “obese.” Risk of mortality increased for those under a BMI of 23 (on the high end of the “normal” BMI range). Many large studies have come to similar conclusions – that higher body weight is associated with greater longevity. Another observation coming from these studies is that BMI is a very unhelpful and inaccurate tool that doesn’t take into account the actual data we have about body size and health.
Winter, J. E., MacInnis, R. J., Wattanapenpaiboon, N., & Nowson, C. A. (2014). BMI and all-cause mortality in older adults: a meta-analysis. The American journal of clinical nutrition, 99(4), 875-890.
2. It’s habits that matter, not body size
This study looked at multiple health-related habits, including smoking and alcohol use, eating fruits and vegetables, and physical activity. They found that adopting healthy behavior changes improved health outcomes, regardless of one’s body size. The chart below shows that as the number of healthy habits increased, the hazard ratio for all-cause mortality decreased. Moreover, when one or more healthy habits were in place, the hazard ratio was pretty much the same, with no differences based on BMI. This study, along with others like it, backs the HAES approach of focusing on behavior changes rather than weight to improve health outcomes.
Matheson, E. M., King, D. E., & Everett, C. J. (2012). Healthy lifestyle habits and mortality in overweight and obese individuals. The Journal of the American Board of Family Medicine, 25(1), 9-15.
3. Weight cycling compromises health, not body size
This prospective study came out back in 1991. It looked at the variability in body weight (weight cycling) of over 5000 men and women. The authors point out that body weight can fluctuate for a variety of reasons, but the most common is due to dieting. With dieting, a person might lose weight quickly, and then put the weight back on, plus a bit more (also called yo-yo dieting for this reason). The authors found that persons with frequent weight cycling had a higher risk of heart disease and mortality than those who remained at a stable weight. This observation was independent of weight or BMI. Thus this study linked dieting with compromised health, rather than weight with compromised health, a result that has since been repeated by other studies.
] L. Lissner, P. M. Odell, R. B. D’Agostino et al., “Variability of body weight and health outcomes in the Framingham population,” The New England Journal of Medicine, vol. 324, no. 26, pp. 1839–1844, 1991.
Could the stress caused by weight stigma be leading to the adverse health outcomes that often get associated with a higher body size? This study is one of several providing evidence for the hypothesis that weight stigma leads to increased stress – which increases one’s risk of various health concerns. The health conditions associated with a stress response include hypertension, heart disease, type two diabetes, and of course, mental health – conditions that are often associated with larger body size. To test this theory, Muennig et al cleverly looked at body image perceptions as a predictor for mental and physical health. Indeed, as the graph below shows, they found as the amount of weight loss a person desired increased, so did the number of unhealthy days they had. Moreover, they found that negative body image was a much higher predictor of unhealthy days than BMI.
Muennig, P., Jia, H., Lee, R., & Lubetkin, E. (2008). I think therefore I am: perceived ideal weight as a determinant of health. American journal of public health, 98(3), 501-506.
5. The Health At Every Size approach has better health outcomes than a weight loss approach
Lastly, here’s a study that specifically looks at a HAES based group program compared to a traditional weight loss group program. This study identified two distinct differences in the groups: in the weight loss group, food restraint and a reduction in body size were encouraged. In the HAES group, food restraint was discouraged (in favor of intuitive eating) and body acceptance was encouraged. The study compared the health outcomes of the women in each group, looking at blood lipids, blood pressure, activity, eating behaviors, and mental health. Both groups showed initial improvements in all aspects; however, the weight loss group returned to baseline in almost all areas at the follow-up, with worsening self-esteem. The HAES group had sustained physical and mental health improvements at the follow-up. Moreover, 53% of the weight loss group participants reported feelings of failure, compared to 0% of the HAES group.
Bacon, L., Stern, J. S., Van Loan, M. D., & Keim, N. L. (2005). Size acceptance and intuitive eating improve health for obese, female chronic dieters. Journal of the American Dietetic Association, 105(6), 929-936
