Health At Every Size®: The Evidence

Updated: May 22, 2020

Popular culture is currently operating with the view that higher body weight causes disease and higher morbidity. At the doctor's office we get evaluated for body mass index, (BMI), and get sorted into categories, such as "underweight" or "obese." People on the higher end of the BMI spectrum are often prescribed weight loss as a treatment for their varied ailments, and doctors often encourage restricting food intake and increasing physical activity.

What follows is a heap of evidence (and it's nowhere near a comprehensive list of the evidence) that this paradigm is fundamentally flawed. It's time to change our thinking, our behavior, our healthcare, and our culture.

Note: this is my most academic and data-laden post to date, so to break up the density of the text, I've sprinkled in these delightful "Goddess Gifs," created by Nina Paley. They're all animations of real-life, totally ancient, effigies found in cultures the world over. These carvings, created by our ancestors, serve as evidence that body size diversity has existed for as long as humans have.

Dieting Doesn't Work

While diet and exercise reliably result in weight loss in the short term, the vast majority of people aren't able to maintain their weight loss in the long run, and they don't experience improved morbidity or mortality (Bacon & Aphramor, 2011). A meta-analyses of 29 weight loss studies showed that participants regained an average of 77% of their initial weight loss after 5 years (Anderson et. al. 2001). 1/3 to 2/3 of people regain more weight than they lost (Mann et al., 2007). “No study – exercise, diet, or surgery – has ever demonstrated long term maintenance of weight loss for any but a small minority”(Mann et al., 2007). And that small minority are at a higher risk of developing an eating disorder because of the intense vigilance required to keep the weight off (Polivy & Herman, 1985).

Not only that, but the act of restricting foods or calories causes bingeing (Polivy & Herman, 1985). Every action has an equal and opposite reaction, so to speak. When we tell ourselves that we're not allowed to have a certain food, or a certain number of calories, our bodies perceive starvation. The body's natural, human reaction to starvation and restriction is to seek out more food. We obsess over what we'll eat when we get the next opportunity, we experience episodes of eating past fullness, simply because our bodies are reacting to scarcity. Failing at diets is normal, and it's also healthy human behavior.

We Have Less Control Over Our Body Size Than We Think

We're told that calories in vs. calories out is a simple formula anyone can follow to achieve weight loss. In one study, "More than 20,000 women maintained a low-fat diet, reportedly reducing their calorie intake by an average of 360 calories per day (Howard et. al., 2006) and significantly increasing their activity. After almost eight years on this diet, there was almost no change in weight from starting point (a loss of 0.1 kg), and average waist circumference, which is a measure of abdominal fat, had increased (0.3 cm) (Howard et. al., 2006)"(Bacon & Aphramor, 2011). We also know that social, trauma-related, economic, and racial factors play a role in determining body size. “Genetic and involuntary environmental contributions to body weight outweigh voluntary lifestyle choices. Body weight is defended by a powerful biological system that reacts to a negative energy balance by lowering metabolism, increasing hunger, food preoccupation, and hedonic responses to food” (Tylka et al., 2014).

Health Is Not Determined By Body Size

Health. is. not. determined. by. body. size.  Health IS influenced by behaviors, and people who practice healthy behaviors can inhabit any sized body.  You can have a healthy blood pressure at any size. You can be cardiovascularly fit and strong at any size.  And you can have diabetes and cardiovascular disease at any size, including a small body!

Most people who are classified as "overweight" or "morbidly obese" live at least as long as "normal" weight people, and often longer (Bacon & Aphramor, 2011). "Analysis of the National Health and Nutrition Examination Surveys I, II, and III, which followed the largest nationally representative cohort of United States adults, determined that greatest longevity was in the overweight category" (Flegal et. al., 2005).

In fact, "obesity" is associated with longer survival than that of thin patients in many diseases, including type 2 diabetes, hypertension, cardiovascular disease, kidney disease, heart attacks, coronary bypass, angioplasty, or hemodialysis. "Obese" senior citizens also live longer than thinner senior citizens (Bacon & Aphramor, 2011).

Yes, larger body size has been scientifically shown to CORRELATE with heart disease and diabetes, but correlation is not causation.  The studies that correlate these conditions with larger body size DO NOT ACCOUNT for confounding factors such as weight stigma and weight cycling (Bacon & Aphramor, 2011). However, both weight stigma and weight cycling HAVE been shown to increase your risk of negative health outcomes.

BMI Does Not Measure Health

The body mass index (BMI) measurement was developed by a statistician in the 19th century in order to assess the weight distribution of a population. It was never intended to hold significance on an individual basis, and it especially wasn't intended as an indication of an individual's health. "BMI is not evidence based [Flegal et. al., 2005], and is being used in the medical community to pathologize certain bodies. The word “overweight” implies there is a weight over which you are definitely unhealthy" (Kinavey & Sturtevant, 2019).

Doctors' treatments for a given ailment vary widely depending on the patient's body size. People at the high end of the BMI spectrum often are prescribed weight loss as the only form of intervention, while small-bodied people receive a completely different protocol for the same illness.

We prescribe behaviors to large-bodied people that we'd diagnose as disordered in small-bodied people. "We tell people with anorexia to stop weighing daily, to stop tracking their food/calories, to stop exercising solely for the purpose of burning calories. But if you are fat, we tell people to do these very things" (Kinavey & Sturtevant, 2019).

Weight Stigma And Health Outcomes

Some examples of weight stigma that people in larger bodies regularly experience as they navigate this world include: people having low expectations of you because of your weight,

being ridiculed at school, hearing negative comments about your weight from doctors, encountering physical barriers and obstacles such as public accommodations being too small, loved ones being embarrassed by your size, being avoided, excluded, or ignored, being stared at, being treated poorly by coworkers/employees, being denied jobs and promotions, and being attacked (Puhl & Brownwell, 2006).

People who experience high levels of weight stigma have more than two times the risk of high allostatic load, increased risk for metabolic and lipid disregulation, impaired glucose metabolism, increased inflammation, type 2 diabetes, hypertension, cardiovascular disease, and mortality. These findings are controlled for BMI, so they're not caused by body size. (Vadiveloo & Mattei, 2017).

It seems to me that fatphobia is one of the last socially acceptable forms of bigotry. So many of us see a larger-bodied person and make assumptions about their lifestyle. We've been conditioned to see large bodies as a moral failing, and some of us are unafraid of making mean-spirited comments to complete strangers in public. So much weight stigma is perpetrated under the guise of "being concerned about someone's health." But if we're really concerned about each others' health, we can't continue to shame each other, knowing what we know about weight stigma's negative health effects.

Weight Cycling And Health Outcomes

Weight cycling is defined by repeated weight loss and regain, and dieting almost inevitably leads to weight cycling. People who experience weight cycling have higher mortality and higher risk of: osteoporotic fractures, gallstone attacks, some forms of cancer, chronic inflammation, muscle loss, hypertension and heart disease (Tylka et. al., 2014). It's possible that weight cycling itself can explain all of the increased risk for heart disease observed in people with higher BMIs (Bacon & Aphramor, 2011).


Health At Every Size®, or HAES®, is an approach to health that was developed by dietitians and other healthcare professionals in the 90's, and the term is trademarked by the Association for Size Diversity And Health (ASDAH). It's principles are:

Weight Inclusivity: Accept and respect the inherent diversity of body shapes and sizes and reject the idealizing or pathologizing of specific weights.

Health Enhancement: Support health policies that improve and equalize access to information and services, and personal practices that improve human well-being, including attention to individual physical, economic, social, spiritual, emotional, and other needs.

Respectful Care: Acknowledge our biases, and work to end weight discrimination, weight stigma, and weight bias. Provide information and services from an understanding that socio-economic status, race, gender, sexual orientation, age, and other identities impact weight stigma, and support environments that address these inequities.

Eating for Well-being: Promote flexible, individualized eating based on hunger, satiety, nutritional needs, and pleasure, rather than any externally regulated eating plan focused on weight control.

Life-Enhancing Movement: Support physical activities that allow people of all sizes, abilities, and interests to engage in enjoyable movement, to the degree that they choose.

Randomized controlled studies that have compared the HAES® model to the weight-normative approach have shown that the HAES® group experienced improved physiological measures (like blood pressure), health practices (like increased physical activity), and psychological measures (like self-esteem and disordered eating). "HAES achieved these health improvements more successfully than models that emphasize dieting. The participants within the HAES groups also demonstrated increased adherence (reduced dropout rates) and no adverse outcomes" (Tylka et. al., 2014). In addition, "no randomized controlled HAES study has resulted in weight gain, and all studies that report on dietary quality or eating behavior indicate improvement or at least maintenance. This is in direct contrast to dieting behavior, which is associated with weight gain over time" (Bacon & Aphramor, 2011).

So what do we do with all of this paradigm-shifting information? Read Part 2 of this series, where I talk about what implementing HAES® actually looks like on the ground, how my herbalism has changed around food, and how my work with clients is much different than it used to be.


Bacon L, Aphramor L. "Weight Science: Evaluating the Evidence for a Paradigm Shift." Nutr J. 2011;10(1):9

Flegal KM, Graubard BI, Williamson DF, Gail MH. "Excess deaths associated with underweight, overweight, and obesity." JAMA. 2005, 293: 1861-1867. 10.1001/jama.293.15.1861.

Howard BV, Manson JE, Stefanick ML, Beresford SA, Frank G, Jones B, Rodabough RJ, Snetselaar L, Thomson C, Tinker L, et al. "Low-fat dietary pattern and weight change over 7 years: the Women's Health Initiative Dietary Modification Trial." JAMA. 2006, 295: 39-49. 10.1001/jama.295.1.39.

Kinavey H, Sturtevant D. "Promoting Body Trust® In Your Work." E-course, 2019.

Mann T, Tomiyama AJ, Westling E, Lew A-M, Samuels B, Chatman J. "Medicare’s search for effective obesity treatments: Diets are not the answer." Am Psychol, 2007;62(3):220-233.

Polivy J, and Herman CP, “Dieting and Binging. A Causal Analysis,” Am Psychol, vol. 40, no. 2, pp. 193–201, 1985.

Puhl RM, Brownell KD. "Confronting and Coping with Weight Stigma: An Investigation of Overweight and Obese Adults." Obesity. 2006;14(10):1802-1815.

Tylka TL, Annunziato R, Burgard D, Danielsdottir S, Shuman E, Davis C & Calogero R. "The Weight-Inclusive versus Weight-Normative Approach to Health: Evaluating the Evidence for Prioritizing Well-Being over Weight Loss." J Obesity; 2014.

Vadiveloo M, Mattei J. "Perceived Weight Discrimination and 10-Year Risk of Allostatic Load Among US Adults." Ann Behav Med. 2017;51(1):94-104.

A special thanks to Hilary Kinavey and Dana Sturtevant at Be Nourished, whose courses have collected many of these references, and to Christy Harrison of Food Psych whose slides from FNCE provided me with many more references.

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