Health at every size

Fat activism isn’t about making people feel better about themselves. It’s about not being denied your civil rights and not dying because a doctor misdiagnoses you.

"Health at every size" (or HAES) is a multi-faceted movement with scientific, social, and a few anti-scientific components. Scientists with a HAES approach look for more effective ways to encourage weight loss and healthy habits. Activists with a HAES approach fight weight discrimination, stigma, and toxic diet culture. Denialists with a HAES approach cherry-pick data to 'prove' that obesity isn't unhealthy.

There's a variety of views in HAES. Good: promoting healthy eating and exercise no matter the weight, encouraging positive thinking, debunking fad diets, not being a jerk to people because of their weight. Bad: denying obesity's health risks, forgetting to try at the "health" part of "health at every size," and denying that obesity is a disease.

HAES can have a positive focus: encouraging heavier people to love and take good care of their bodies, and to not be afraid to do things like swimming or working out. Research shows that exposure to the HAES movement leads to better health outcomes and even weight loss. People who don't hate their bodies may put more effort into taking care of them.

But some proponents of the HAES may ignore their own doctors' advice to lose weight because there can't possibly be any link between obesity and disease. However, doctors can miss other diseases if they only focus on the patient's weight. If you are concerned, ask your doctor to consider other possible reasons, make sure any refusals to conduct certain diagnostic checks are well-documented, and don't be afraid to get a second opinion if your doctor won't take treatment seriously.

Causes of obesity
The traditional understanding of obesity has centered diet and exercise as key determinants of weight. This has led to the common perception of obesity as being solely a product of poor self-control. However, recent scientific research, especially in the last decade, has pointed to a range of genetic, environmental, and socioeconomic factors that influence weight. These collectively suggest that obesity may be more complex than previously thought.

HAES seeks to advance the scientific understanding of obesity and in doing so improve the lives of fat people. The movement has several good points, but not all its claims are backed by scientific evidence. Some of this is due to lack of research. Researchers have found that a HAES (or "weight-inclusive") approach is linked with better physical health, better mental health, and healthier habits overall.

Genes and environment play a notable role
Research has shown there are many genetic, epigenetic, and environmental factors that shape our bodies. It has been estimated that obesity is 40-70% heritable. One study found that 80% of the children of two obese parents were obese, while only 14% of the children of average-weight parents were obese.

The posits that the human propensity for obesity may be a byproduct of our evolution. For early humans, the ability to store energy as fat during periods of plenty would have been advantageous, allowing them to better endure times of reduced food availability, and increasing their chances of surviving famine. However, in the modern societies with more stable food supplies, this fat-storing tendency has seemingly become detrimental. This could explain why obesity rates rose alongside the wider availability of refined grains and sugars that followed the Industrial Revolution. It might also explain why certain traditionally non-agrarian human populations, such as the of Arizona and the  of the Pacific, developed some of the highest rates of obesity after being introduced to a Western lifestyle.

Increased obesity rates can also arise from epigenetic factors. Famine can significantly alter how genes are expressed, and these changes may be passed on to successive generations. People in utero during the of 1944-45 tended to have higher-than-average birth weights, and were also more susceptible to obesity, diabetes, and high cholesterol in later life than people born before or after the famine. They also had a higher mortality rate sixty-eight years later. At least one study also found that the grandchildren of Dutch famine victims had higher birth weights.

Other environmental factors play a role. A meta-analysis of 240 studies found a link between certain plastics (PCBs, phthalates, and BPA) and increased rates of obesity and diabetes. Another meta-analysis of 100 studies found a link between dietary exposure to antibiotics used in meat production and an increased risk of obesity, suggesting changes in the microbiome, i.e. the bacterial ecosystem of the human digestive tract, as a cause.

Healthy eating isn't simple for everyone
Maintaining a healthy diet is generally sound advice. However, it presumes that everyone has equal access to good, nutritious food. This isn't always true for marginalized and low-income people. Poverty is associated with an increased risk of obesity. Fresh vegetables and meat can be prohibitively expensive for the poor, leading them to opt for cheaper, unhealthier food choices. These typically include energy-dense foods like potatoes and processed meat products, which are more palatable, have a longer shelf life, and allow poor families to maintain energy intakes at a lower cost than more expensive, less-energy-dense foods. However, energy-dense foods tend to have higher fat and sugar content, and are thus more unhealthy. Nonetheless, agricultural advancements have made energy-dense foods widely available, and they now comprise 30-50% of the Western diet.

Some people live in "" with less access to affordable and nutritious food. These areas are typically poor, minority, or rural communities. They often lack supermarkets, leaving residents with less food options and leading them to rely on convenience stores and fast-food restaurants, which offer cheap, energy-dense foods.

Special dietary needs can also limit one's food options in a way that makes healthy eating more difficult. Irritable bowel syndrome sufferers may find healthy-diet staples like leafy greens aggravate their symptoms, and may thus favour starchy and low-fiber foods in an attempt to alleviate them. IBS has been linked to an increased risk of obesity by a number of studies. Autism, with its attendant sensory sensitivities and need for routine, can also cause dietary restrictions that pose challenges for healthy eating. Studies have found a link between autism and an increased risk of obesity.

Diets often don't work and can be harmful
Traditional dieting is often ineffective and can be harmful in the long term. Recent scientific research has shown that dieting, especially using unhealthy means, is correlated with eating disorders, weight fluctuations, extreme dieting measures (such as laxatives), reduced self-esteem, increased susceptibility to weight gain, and other long-term health issues.

Willpower alone doesn't explain dieting failure. A meta-analysis found that diets generally do not work, and that many dieters regain more weight than they started with initially. Up to 80% of dieters regain some or all of the weight within a year. Diets can alter metabolism and hormone balance in ways that contribute to weight gain and retention. The human body has seemingly been hardwired by evolution to respond this way to apparent food scarcity (see the discussion of the thrifty gene hypothesis in the previous section). This "famine reaction" leads to a reduced resting metabolism, meaning the body burns less calories and stores more fat, and this lowered metabolic rate may persist even as weight is regained. Major weight loss can be metabolically identical to starvation. It can also trigger increased production of ghrelin, a gastric hormone tied to hunger, and decrease peptide YY and leptin, hormones associated with hunger suppression. These hormonal changes may also persist long after the initial weight loss. All this means that not only are lost pounds regained, but subsequent weight loss attempts are more difficult. People who want to stay in shape must also adhere to stricter diets and exercise more than just three decades ago due to an apparent shift in biological and environmental factors. A study found that people in 2006 had higher BMIs than people of the same age who followed an identical diet and exercise regimen in 1988.

Reduced caloric intake can increase cortisol production and psychological stress. Excessive cortisol, often known as the "stress hormone," can have several health consequences. Not only does it cause weight gain, but it is associated with depression, anxiety, and sleep problems. It can also negatively impact the cardiovascular system, and has been linked to an increased risk of heart disease.

Fad diets are especially awful for losing weight. More dangerous fad diets may even result in death. A woman in the UK died as a result of following a breatharian diet. Weight cycling, or "yo-yo dieting," increases heart disease and mortality. Some studies have found that the weight fluctuations associated with "yo-yo dieting" may have worse health outcomes than a stable (even overweight) weight.

It can be difficult to measure how strictly someone follows a diet. Dieters may under-report the number of calories that they eat and/or over-report the exercise they do. This means that they may not be following a diet as well as they think they do.

New approaches to healthy living
Due to the lack of positive results associated with diets, experts are now calling for a new paradigm, favoring smaller and sustainable gradual lifestyle changes over strict diets. A meta-analysis found that several practices improve body image and lead to better health: intuitive eating, Cognitive Behavioral Therapy, self-compassion, and exercise.

Weight-neutral interventions that advocate a shift away from traditional dieting show improvements in mental health and disordered eating habits, as well as positive or neutral effects on biological markers of health. Weight-neutral approaches such as Health at Every Size are a scientifically valid way to improve health, especially with regards to psychological well-being and healthy habits.

Intuitive eating
HAES advocates promote intuitive eating, which encourages people to pay attention to their appetite rather than relying on self-imposed rules. One must eat until satisfied, and then stop. While intuitive eating sounds like regular behavior, it is something that chronic dieters and eating disorder survivors may need to re-learn.

Multiple literature reviews have found that intuitive eating is associated with lower BMI, healthier eating habits, and better psychological well-being, while noting that it is still an emerging topic.

The practice has a few limitations: it focuses on when to eat (not what to eat), and it may not work well for people who have health conditions that impair their interoception, meaning that they cannot recognize hunger and fullness properly. Interoception issues can occur in a number of conditions, such as eating disorders, depression, autism, anxiety, and more. Someone who cannot recognize hunger properly may need to implement common-sense habits to make sure that they are eating enough.

Weight loss programs
"Failed" child obesity reduction programs have improved other measures of health, including athletic skills, time spent exercising, and time spent watching television. Health programs for kids may not significantly change obesity, but they can improve test scores. Seeing weight loss as the end goal of such initiatives can result in overlooking positive changes.

Negativity won't cause positive outcomes
Research suggests that negative and stigmatizing approaches to obesity don't lead to better health. A 2014 study found that fat shaming doesn't just fail to motivate weight loss, but, paradoxically, may actually prompt weight gain. This may be because stigma creates a vicious cycle, causing increased stress that triggers binge or comfort eating, thereby leading to more weight gain. In two studies, Schvey et al. found that, in obese women, exposure to weight-stigmatizing content increased caloric consumption and production of cortisol. Major et al. (2014) found similar results, concluding that exposure to "weight-stigmatizing news messages" causes obese (but not non-obese) individuals to "consume more calorie-rich snack foods" and "feel less able to control their diet." Obesity and internalized shame have been linked to a greater incidence of depression and anxiety. Heavy people who feel discriminated against have shorter lifespans. Around half of girls between ages 3 and 6 are worried about their weight, and preschoolers are less kind to their chubbier peers.

Weight stigma can also strongly discourage physical activity among obese people. Harassment, body-shaming, and judgment faced in public facilities like gyms and swimming pools can lead people to avoid them. In a 2011 study, experience of fat shaming, internalization of "anti-fat attitudes," and internalization of societal beauty standards were all found to be associated with exercise avoidance (particularly at gyms).

Additionally, fat people often face discrimination in hiring and salaries, further leading to marginalization.

Weight stigma leads to worse healthcare
Doctors repeatedly advise weight loss for fat patients while recommending CAT scans, blood work or physical therapy for other, average weight patients.

Stigmatization and shame often follow fat people into the doctor's office. Researchers have found that negative bias can lower the quality of healthcare provided to obese patients. Physicians in one study reported they prefer to spend signficantly less time with obese patients. They were also more likely to rate them poorly in 12 out of 13 categories, including perceptions of self-discipline and health consciousness. Another study found that physicians tend to build less rapport with obese patients and are less likely to offer them empathy or reassurance. Nurses can also hold negative attitudes towards heavier patients.

The issues arising from weight stigma in medicine are two-pronged. Patients may delay or avoid seeking care if they fear being judged, shamed, or dismissed, and doctors may misdiagnose or overlook symptoms if they focus inordinately on weight. Beyond eroding the doctor-patient relationship, this can lead to serious medical conditions going undiagnosed, or not being caught until they are more severe and possibly untreatable. A review of 300 autopsy reports found that obese patients were 1.65 times more likely to have previously undiagnosed serious medical conditions. Studies have consistently shown that obese women are less likely to be offered or seek screening for several cancers (breast, cervical, colorectal, and ovarian) and more likely to be diagnosed at a more advanced stage. This problem is compounded for women of color.

Poor-quality healthcare are particularly concerning in light of the US Preventative Services Task Force's recommendation that regular check-ups and extra support are ideal for patients seeking to lose weight.

HAES doesn't address all health concerns
Research has shown that obesity is linked to a number of health issues. These include increased risks of cardiovascular disease, diabetes, musculoskeletal disorders (especially ), and certain cancers. Childhood obesity carries not only and an increased risk of obesity and its associated health problems in adulthood, but also presents additional risks including breathing difficulties, increased susceptibility to bone fractures, hypertension, and insulin resistance.

While some research suggests that an HAES approach may yield better health outcomes than more traditional, diet-centered approaches, it does not address all of the health risks associated with obesity. Some claims made by HAES advocates lack scientific evidence and veer toward denialism. In particular, some hardline HAES advocates consider any attempt to lose weight by restricting one's caloric intake to be a precursor to, or even a symptom of, anorexia. This suggests poor understanding of eating disorders. Anorexia involves a compulsive, overriding obsession with weight loss and food restriction, as well as distorted self-perception. This is different from altering one's diet to cut down on or avoid less-healthy foods. Eating healthier food can have positive effects other than weight loss. Research has shown that purposely trying to lose weight, even if unsuccessful, can reduce mortality risk for overweight patients with diabetes.

Healthy habits are important regardless of size. Matheson et al. (2012) found that four healthy behaviors – not smoking, drinking moderately, exercising regularly, and eating at least five portions of fruit or vegetables per day – were associated with reduced mortality for all weight classes. However, another analysis has shown that flaws in methodology can dramatically understate the mortality risk of obesity. Obese people may be metabolically healthy, but precisely how many are is unclear, as a literature review found numbers ranging from 6% and 75%. This wide range of results is due in part to differences in the definition of metabolically healthy obesity across studies. Some studies categorize individuals with up to two components of metabolic syndrome as metabolically healthy, while a person is considered to have metabolic syndrome if they have at least three risk factors, one of which is obesity. People with a normal BMI with metabolic syndrome are also twice as likely to get diabetes than obese people with healthy blood metabolic indicators, but a higher BMI still increases the risk of diabetes regardless of metabolic indicators.

Obesity paradox
The is a medical hypothesis which posits that obesity, against conventional wisdom, may be associated with greater survival for certain diseases and/or groups of people. This paradox was first noted in 1999 when it was found that obese hemodialysis patients fared unexpectedly well. It has since been observed in patients with other conditions, including heart failure, acute coronary syndrome, and chronic obstructive pulmonary disease (COPD). One meta-analysis found that "not only overweight but also obesity is protective" for elderly nursing home residents. The cause or causes of this paradox are undetermined. Hong et al. (2011) have proposed that adipose tissue may store fat-soluble pollutant chemicals, thus locking away toxins that would otherwise harm the body.

The obesity paradox has drawn criticism. Studies that show that obesity reduces mortality rates for certain diseases may neglect to account for confounding factors. In a study reviewing 10 years of CDC data, it was found that the obesity paradox disappeared once weight history was controlled for, i.e. by separating individuals in the normal weight category whose weight had remained stable from those who had previously been obese.

Potential conflicts of interest have also raised suspicions about whether the obesity paradox truly exists. It is strongly suspected that Coca-Cola is championing studies that promote the obesity paradox, has a relationship with cardiologist Carl Lavie who popularised the obesity paradox, and even more suspiciously, is funding researchers that promote the obesity paradox.