British Prime Minister Boris Johnson recently unveiled a “Better Health” campaign to combat obesity. The announcement was prompted by Johnson’s bout with COVID-19, which included a stint in intensive care in April. Johnson is convinced that his reported Body Mass Index of 36 (30 is considered obese) was responsible for the severity of his infection and is now on a mission to slim down the United Kingdom.

Johnson’s proposed interventions include banning junk food advertising before 9 P.M. to reduce the likelihood that children would be exposed to such ads, preventing stores from selling unhealthy snacks at entrances and checkouts, barring “buy one get one free” promotions on unhealthy foods, and requiring restaurants with over 250 employees to post calorie counts. Other measures include encouraging doctors to prescribe cycling (Johnson’s favored mode of transportation) and facilitating access to weight-loss programs.

Critics of Johnson’s anti-obesity measures rightly charge that they are incomplete because they focus on personal responsibility rather than attacking the root causes of obesity—poverty and inequality. Others have pointed out in the past that calorie counts in restaurants have negligible effects on consumer behavior.

As a researcher and educator on the history and politics of obesity, I would also caution that Johnson and lawmakers from other countries who might follow in his footsteps should tread carefully. Weight is a delicate issue, and mishandling “wars” on fat or obesity could impair, rather than improve, the physical and mental health of people with obesity.

This is not to say we should ignore links between obesity and COVID-19. There is mounting evidence that, obesity is the most significant risk factor in serious cases of COVID-19, possibly second only to age. Studies of populations in China, Italy, the United States, France and Britain have shown that people with obesity may double their risk of being hospitalized or dying from COVID-19, and that relationships between weight and COVID-19 are particularly pronounced among younger people and men.

Forty-two percent of American adults are classified as obese.

There are a number of explanations as to why obesity can aggravate COVID-19 infections. Scientists have found that COVID-19 often enters the body through an enzyme called ACE2, and that people with fat tissue have more ACE2 receptors and are therefore more susceptible to infection and higher viral loads.

Once infected with COVID-19, some doctors have proposed that because fat tissue compresses the diaphragm and lungs, those with obesity experience greater difficulty breathing. Another popular theory is that obesity may interfere with the proper functioning of immune cells and trigger an excessive immune response called a “cytokine storm,” resulting in potentially life-threatening inflammation and organ failure. Some researchers have also suggested that irregular levels of hormones associated with obesity, like glucose-regulating adiponectin and weight-regulating leptin, compromise immune responses to the virus.

As researchers continue to investigate links between obesity and COVID-19, countries and public health organizations would be well advised to devote renewed attention to obesity. In doing so, public health initiatives must learn from the mistakes of previous campaigns that stigmatized people with obesity as lazy, weak-willed and gluttons for junk food.

In 2012, both Children's Healthcare of Atlanta (Georgia largest pediatric health care system) and Blue Cross and Blue Shield of Minnesota launched controversial ad campaigns that critics have justly characterized as fat shaming. One Georgia poster featured four overweight children, with captions such as, “Big bones didn’t make me this way. Big meals did.” Meanwhile, the Minnesota ads targeted parents. One of its commercials featured a large man at a fast food outlet carrying a tray of burgers, hot dogs, fries, onion rings and sugary beverages. As the man blithely walked toward his booth, he overheard his overweight son in competition with another boy over whose father could eat the most. He suddenly felt ashamed.

I fear that these types of misguided ads and anti-obesity campaigns might resurface in the COVID-19 era, and that the pandemic will provide added ammunition to the notion that people with obesity are social and medical scourges. Overweight children may be subjected to more bullying by peers if there are internet ads, commercials, posters and billboards stigmatizing people with obesity and their alleged diet and exercise habits.

Among adults, anonymous commentators of news stories about COVID-19 are already posting that people’s fates are the result of “poor lifestyle habits,” a claim reminiscent of the 1980s and early 1990s when anti-gay voices maintained that people died of AIDS because of the “homosexual lifestyle.” Furthermore, stigmatizing people for their weight would be inimical to the current reckoning with racial injustice, as African American women and Latino children are the most disproportionately affected by obesity in the United States.

To those who insist that blunt messaging is necessary to underscore the gravity of obesity just as sensationalistic anti-tobacco ads were needed to drive home the dangers of smoking, public health research has shown that not only is stigma ineffective, it can induce people with obesity to gain rather than shed, pounds.

Studies have found that both children and adults subjected to weight-based bullying or discrimination are more likely to seek solace in binge-eating, to develop eating disorders and to be discouraged from exercise due to anxieties about their bodies being on display. Stigmatizing people for their weight could also impair mental health and create added stress, which could result in elevated levels of the stress hormone cortisol and increased heart rate, blood pressure, and weight.

To avoid these consequences, campaigns to reduce obesity should focus on the positive aspects of maintaining healthy diet and exercise habits. And because lower-income Americans and racial minorities are more likely to live in neighborhoods with comparatively fewer supermarkets and green spaces, public policy interventions should also ensure access to affordable healthy foods and spaces that facilitate exercise and recreation. Such interventions align with the consensus among obesity experts that weight is the function of the interaction between genes and the environment.

Finally, it is imperative that anti-obesity initiatives also include an educational component in which the public and even health care providers are informed about the effects of weight bias. Rebecca M. Puhl and Chelsea A. Heuer, leaders in this area of research, point to studies revealing that health professionals sometimes regard patients with obesity as “lazy, lacking in self-discipline, dishonest, unintelligent, annoying, and noncompliant with treatment,” and that medical appointments with heavier patients are shorter than those with thinner patients.

Patients with obesity perceive these slights, reporting that health care providers do not take them seriously, erroneously assume that their weight is responsible for all their ailments, and condescend to them about losing weight. Hospital gowns, examination tables and medical equipment that are not designed for larger bodies exacerbate the embarrassment and indignities they experience. As a result, patients with obesity may forgo subsequent medical care, including lifesaving cancer screenings.

On the surface, at least, Boris Johnson seems to have come to appreciate the importance of approaching obesity with more compassion. In 2004, he wrote a newspaper column headlined “Face It: It’s All Your Own Fat Fault.” Now, he reassures the British public that his anti-obesity program is not meant to be “excessively bossy or nannying,” adding: “We want this one to be really sympathetic to people, to understand the difficulties that people face with their weight, and just to be helpful.”