Science is full of weight and racial bias

Analyzing science-based health advice for weight and racial bias

There is significant weight and racial bias in science. This bias means that parents need to be careful consumers of scientific media and health recommendations. Otherwise, we perpetuate weight and racial biases in our homes and pass them along to our children.

Most scientists are not intentionally fatphobic or racist. But science is dominated by white people. Only 13% of scientists are neither white or Asian. Most scientists make the assumption that weight is a causative factor in disease, despite the fact that there is no causal evidence. In fact, high body mass is a very weak predictor of mortality and may even be protective in some cases.

Science cannot show a causal link between weight and disease. And they continuously recommend weight loss. But the only proven outcome of intentional weight loss is weight regain. The scientific and medical communities have deeply rooted weight bias. And the bias remains largely unseen and unexamined.

When consuming science media that links weight to health, we need to consider the following facts: 

  • We live in a heavily biased society
  • Our society favors thin, wealthy, white people
  • Scientists are people first (i.e. not immune to societal forces)
  • We must assume that most science has weight and racial bias

It’s up to us to teach our kids to be critical consumers of all media, including scientific papers. Nobody will expose weight and racial bias in science for us. Here is a demonstration of how we can take a critical lens to scientific health recommendations. 

A parents’ guide to analyzing science-backed health recommendations

Let’s look at the American Cancer Society Guideline for Diet and Physical Activity for Cancer Prevention, published by the American Cancer Society Journals, June 9, 2020.

Recommendations for individuals:

  • Achieve and maintain a healthy body weight throughout life.
  • Be physically active.
  • Follow a healthy eating pattern at all ages.
  • It is best not to drink alcohol.

We will take a deeper dive into the weight bias, racial bias, and corporate influence contained in these recommendations. Our premise is that this paper demonstrates weight and racial bias in science.

Recommendation 1: Achieve and maintain a healthy body weight throughout life

Keep body weight within the healthy range, and avoid weight gain in adult life.

Problem 1: Unclear causative link between weight and cancer

Nearly 40% of American adults are considered obese* but not all of those people get cancer. And cancer does not only affect people who are overweight and obese. Approximately 38.4% of men and women will be diagnosed with cancer at some point during their lifetimes. It may be true that slightly more than 40% of people who get cancer are obese. But that does not mean that being obese causes cancer.

Weight is largely a result of genetics and environment. And we know that genetics and environment are also risk factors in cancer development. Therefore, scientists cannot say that obesity causes cancer. All they can say is that it’s possible that the same conditions that cause cancer also cause obesity. In fact, the authors acknowledge that the 2016 IARC expert working group found that the evidence on weight loss and cancer risk was insufficient to evaluate.

*The terms “obese” and “obesity” are objectionable. They they are medicalized terms intended to pathologize a human body doing what it was naturally designed to do in response to genetic and environmental conditions. We use the term here with extreme caution.

Problem 2: what is “healthy body weight?”

The authors define weight based on BMI (body mass index), which is based on the height and weight of a person. Researchers from the Perelman School of Medicine stated that BMI is an inaccurate measure. Because it does not take into account muscle mass, bone density, overall body composition, and racial and sex differences.

Furthermore, the BMI categories for “healthy” changed in the 1990s. The World Health Organization (WHO) significantly adjusted the categories of “overweight” and “obese.” This means that millions people went to bed one night in the “healthy” range and woke up “overweight.” This arbitrary change in BMI standards accounts for many of the alarmist headlines regarding the “obesity epidemic” that have proliferated in the past 30 years. 

Additionally, weight is a racial issue. The prevalence of obesity varies considerably among racial/ethnic groups:

  • Asian: 12.7%
  • White: 37.9%
  • Hispanic: 46.8%
  • Black: 47.0%

A Black person is 10% more likely to be obese compared to a white person. This shows how both weight and racial bias can creep into science. In fact, Sabrina Strings and others say that weight bias is rooted in racism.

Problem 3: How can people “achieve and maintain” a certain weight?

The authors do not spell out how exactly a person is supposed to “achieve and maintain” a “healthy weight.” Nor do they define exactly what “healthy” weight is (other than to refer to BMI). But anyone who is alive today knows that to “achieve” a “healthy weight,” we need to engage in intentional weight loss. It’s the same if we want to “maintain” a “healthy” weight. Maintenance requires vigilant weight oversight and intentional weight loss when weight inevitably creeps up.

There is no proven, effective, and safe method to intentionally lose weight. In fact, weight loss efforts come with significant side effects, including increased levels of cortisol. This is of special note since cortisol is linked to cancer risk. So recommending that people “achieve” a certain weight, which is presumably through weight loss efforts, actually increases cancer risk. 

A second known side effect of intentional weight loss is weight cycling. In fact, about 95% of people who intentionally lose weight will regain the weight they lost. And more than half will gain more. This creates a cycle of weight gain and weight loss. Weight cycling results in higher lifetime weight and increases mortality. Thus anyone who has ever sought to “achieve” a lower weight is likely to weigh more and be sicker than if they had not done so. 

It is notable that the authors specifically recommend specific behavioral changes for the other recommendations. But they offer none for this first (presumably most important) recommendation.

Problem 4: Weight is not a modifiable behavior

This paper aims to provide behavioral recommendations for individuals who wish to prevent cancer. However, this first guideline assumes that weight is a modifiable behavior. Weight is not a behavior, it is a physical fact.  

In fact, body weight is largely genetic and environmental. It is 70%-80% heritable, which is as closely related to genetics as our height. (And nobody is asking us to achieve a “healthy height” – that would be bizarre.) The next greatest impact on our weight is our environment. Everything from our neighborhood to our society and food sources influence our weight more than our individual makeup. 

We cannot actually control our weight without significant health side effects. But we believe we can because of the $72 billion weight loss industry. Their marketing strategy is simple. They shame us for gaining weight, then are part of the reason we gain weight again. They are always there to take our money when we inevitably regain weight. Then the cycle begins again.

And it is undeniable that the weight loss industry has directly funded obesity and weight research, making it deeply questionable. This is like the tobacco industry funding lung cancer research.

Most people cannot control their weight. And those who attempt to do so either drive their lifetime weight higher or develop an eating disorder

Recommendation 2: Be physically active

Adults should engage in 150 to 300 minutes of moderate‐intensity physical activity per week, or 75 to 150 minutes of vigorous‐intensity physical activity, or an equivalent combination; achieving or exceeding the upper limit of 300 minutes is optimal.

Problem 1: Unclear link to cancer prevention and dose recommendation

The authors state that 1.5% of all cancers diagnosed in the United States are attributable to physical inactivity. However, they later state that beyond colon cancer, the strength of the evidence is inconsistent. Finally, they state that drawing clear recommendations for activity dose and intensity for cancer risk reduction is “challenging.”

What this says is that while these scientists assume that physical activity will prevent cancer, they cannot prove it. Furthermore, they cannot actually back up their recommendations based on scientific study. In other words, this is a recommendation based on assumptions, not science.

Problem 2: Racist recommendation

The authors recognize that these recommendations are difficult for less privileged racial minorities. They acknowledge that there are significant social, environmental, and economic barriers to exercise. For example, limited access to safe outdoor areas, the economic ability to invest in fitness, and a white-oriented fitness industry all make this recommendation out of reach for many Black people.

According to the 2018 Sports & Fitness Industry Association Topline Participation Report, rates of inactivity among the poorest households has increased. Meanwhile, activity levels have increased for more affluent households. As the SFIA puts it: “The affluent are getting more active while the less affluent are becoming more inactive.”

Poverty is broken down along racial lines (2018 US Census):

  • Native American: 25.4%
  • Black: 20.8%
  • Hispanic: 17.6%
  • White: 10.1%
  • Asian: 10.1%

This paper makes a health recommendation that is racially skewed and unattainable for our most vulnerable populations.

Recommendation 3: Follow a healthy eating pattern at all ages.

A healthy eating pattern includes: Foods that are high in nutrients in amounts that help achieve and maintain a healthy body weight; A variety of vegetables—dark green, red and orange, fiber‐rich legumes (beans and peas), and others; Fruits, especially whole fruits with a variety of colors; and Whole grains.

Problem 1: Unclear link to cancer prevention

As with weight and exercise, there is an unclear link between food and cancer. The authors estimate that 4.2%‐5.2% of cancer cases are linked to to poor diet. But they admit this is a problematic concept to investigate. They say: “Determining the role of diet in cancer prevention is challenging, because consumption patterns of humans are highly complex, the food supply is constantly changing, and relevant exposure periods are not always known.” Additionally, “most current evidence concerning diet and cancer prevention is derived from observational epidemiologic studies.”

In other words, this is not objective scientific study. It is observational research, which is inevitably impacted by human bias. We have been told for decades that “healthy” food impacts cancer risk. Therefore it is impossible that researchers do not bring this powerful bias to their observational studies. 

Problem 2: Racist recommendation

The authors make these recommendations despite the fact that they also see how difficult it will be for racial minorities to meet them. In fact, they acknowledge that: 

“Communities with a greater proportion of ethnic minorities and residents with low socioeconomic status are often characterized by fewer supermarkets with healthy, affordable, high‐quality foods. In these areas, residents may not have the economic resources to purchase adequate and nutritious food.”

These communities are also more likely to be experiencing food insecurity. This is defined as being without reliable access to a sufficient quantity of affordable, nutritious food. In 2018, an estimated 1 in 9 Americans were food insecure. That’s more than 37 million Americans, including more than 11 million children.

And, like all of the recommendations in this paper, this is a racial issue. According to the USDA, 22.5% of Black households and 18.5% of Hispanic households are food insecure. This is higher than the national average of 12.3%. How can we ask people who are already starving to improve their diets with more green, leafy vegetables? This recommendation misses our most vulnerable populations completely.

Recommendation 4: It is best not to drink alcohol

We will spend the least time on this recommendation. It is the only recommendation for which there is a clear link to cancer.

Alcohol consumption is an established cause of at least 7 types of cancer: cancers of oral cavity, pharynx, larynx, squamous cell carcinoma of the esophagus, liver, colorectal and female breast cancers.

Deep in the article, the authors state: “… there is no safe level of consumption. The evidence indicates that the more alcohol a person drinks, the higher his or her risk of developing an alcohol‐associated cancer. The risk of some cancers increases at even less than one drink a day. No type of alcohol beverages (e.g. beer, wine, liquor) is less risky in terms of its impact on cancer risk.”’

That’s a much stronger statement than “It’s best not to drink alcohol.”

Alcohol consumption and society

Approximately 50% of Americans over the age of 12 report alcohol consumption. And racial bias may (once again) be involved here. Alcohol abstinence is higher among Hispanics, Blacks, Asians, and Native Americans than among non‐Hispanic whites

This is the only item on the list that has a causal link with cancer. Why is it last on the list? The authors say that any consumption of alcohol causes cancer. Yet they soft-pedal the recommendation by starting with “it is best.” Why?

The authors say that alcohol caused 5.6% of all cancer cases. Meanwhile, exercise, the second recommendation, causes 1.5%, and nutrition is linked to 4.2%‐5.2. In other words, alcohol has the second-highest link to cancer in this paper, yet is listed fourth.

This is where it pays to take a look at the paper’s disclosures. Scientists are required to mention their funding sources. And, guess what? The authors of this paper receive funding from the diet and alcohol industries. The alcohol industry is valued at $72 billion, and very powerful. Could that be why this recommendation comes last and is couched in such gentle language?

Final analysis

We need to think about why there is no recommendation for reducing toxic, chronic stress. The link of stress and cancer is at least as strong as that of exercise and food choices. Yet it is not listed at all. Here again we must think about science through a weight and racial bias lens. The populations that experience the most chronic stress are racial minorities.

Specifically, Black and other racial minorities experience chronic systemic racism that negatively impacts their health. The fact that the authors left stress off the list suggests racial bias. Also, each of the four items listed happens to have a large industry attached to it. Eliminating racism does not.

When you first see this paper, you may take the recommendations at face value. You may decide it’s time for your family to lose weight, start exercising more, and eat “healthier.” You may even cut down your drinking for a little while.

But it’s important not to take scientific recommendations at face value. We must investigate science and learn to recognize weight and racial bias. There are serious consequences for making assumptions about health based on weight and racial bias.

First, we damage people’s health with weight bias. It is considered a toxic stressor which is linked to cancer and other deadly diseases. Next, we whitewash health recommendations, failing to consider racial diversity and social justice. Health is a social justice issue. We need to pursue racial justice for our own families, our communities, and our society at large.  


Learn more about racism and weight stigma:


Ginny Jones is the editor of More-Love.org. She writes about parenting, body image, disordered eating, and eating disorders. Ginny is also a Parent Coach who helps parents handle their kids’ food and body issues.

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