Groundbreaking weight-loss drugs like Ozempic and Wegovy have understandably generated a lot of excitement, bringing hope to the hundreds of millions of people grappling with obesity. When combined with a healthier diet and exercise, these drugs, which suppress appetite, deliver an average 10% reduction in body weight that can be sustained for years.

With more than two-thirds of adults in the United Kingdom and nearly three-quarters in the United States classified as overweight or obese — a health crisis that costs national economies billions of dollars annually — physicians and policymakers could be forgiven for embracing these drugs as a panacea. President Biden’s administration, for example, recently proposed requiring Medicare and Medicaid to cover the costs of weight-loss drugs, which would expand access for millions of Americans. But addressing obesity requires much more than a technological fix.

We ultimately also must address the root cause of the global obesity crisis: our broken food system.

The alarming rise in obesity over the past 30 years is not simply a byproduct of higher living standards or more sedentary lifestyles. The primary factor appears to be the transformation of our food environment, which has fundamentally altered both the types of food we consume and our eating habits.

In recent years, scientists and health experts have increasingly focused on foods high in fat, sugar and/or salt, which drive unhealthy dietary habits. Companies have reshaped the food system to produce ultraprocessed, hyperpalatable and highly profitable foods, leading people to snack more, eat larger portions and prepare fewer meals themselves. In the U.K., for example, the snack market has boomed while the time spent preparing meals has sharply declined.

These changes haven’t just fueled the rapid increase in consumption of salty, fatty, sweet foods. They have also led to a surge in meat consumption, especially in Europe and North America, where meat-heavy diets have become common.

Beyond the heightened risk of heart disease and related health conditions, excessive meat consumption has had devastating effects on the climate and biodiversity. Research shows that animal-based foods generate twice the greenhouse gas emissions of plant-based alternatives. Just as health experts urge us to reduce our intake of salt, fat and sugar, climate scientists consistently emphasize the importance of curbing meat and dairy consumption to keep global warming within safe limits.

In an effort to prevent a lasting change in people’s eating habits, the meat industry is seeking technological fixes to cut greenhouse emissions. For example, funding for research on cutting farm emissions — such as feed additives designed to reduce methane levels in cows’ burps — has increased markedly.

Such solutions are particularly attractive to governments reluctant to introduce measures that influence consumer behavior. Fearful of opposition from the Big Food lobby and wary of accusations of overreach, policies like sugar taxes or meat taxes are deemed political hot potatoes to be avoided at all costs.

But the overlapping crises our broken food system is fueling — from the billions of dollars spent each year on diet-related health problems to the environmental degradation pushing our planet to its limits — cannot be wished away or fixed with technological tweaks. Instead, what is needed is a major shift in dietary habits toward foods that nourish both people and the environment.

To this end, the Eat-Lancet Commission — comprising the world’s leading nutrition and sustainability experts — advocates consuming a diet rich in fresh fruits and vegetables, whole grains and plant-based proteins while reducing consumption of animal proteins, dairy and sugars. Taken together, these recommendations offer a clear blueprint for ensuring health and sustainability.

It is unrealistic to expect consumers — conditioned by food environments designed for profit rather than human or environmental health — to drive this transition on their own. With unhealthy foods widely available and aggressively marketed, many consumers struggle to moderate their food intake, and in some cases they even develop addictive behaviors.

Governments and food manufacturers must take proactive measures to reshape these environments, such as expanding the agendas of campaigns planned to take aim at reducing the consumption of salt, fat and sugar to also take aim at meat, thereby encouraging people to eat more plant-based whole foods and meat alternatives.

Another potential solution would be to extend some nations’ bans on promotions for unhealthy foods to cover meat products. Requiring food companies to report on the types of food they sell, including salty, fatty and sweet foods and the ratio of plant-based to animal proteins, would also help. These measures would encourage businesses to prioritize healthier, more sustainable options over less nutritious ones.

None of this is to suggest that the new generation of weight-loss drugs cannot benefit individuals living with obesity. For those trapped in a cycle of poor health, treatments such as Ozempic and Wegovy could even save lives, and efforts to make these treatments widely available are a welcome step.

But it is essential that we recognize that this approach merely interrupts one mechanism of obesity rather than eliminating the underlying pathology. Defusing the time bombs of ill health and environmental catastrophe requires fast, decisive action to remake our dysfunctional food system.

Emily Armistead is interim executive director of Madre Brava, a research and advocacy group.

Polio came for 5-year-old Lynn Lane when she was visiting her grandmother in rural Indiana. Suddenly, her arms and legs became weak, and by the time she got to a hospital in Indianapolis, she was totally paralyzed and in respiratory failure. Lane spent the next several months in an iron lung.

“I don’t really remember too much about that,” Lane, now 73, told me Monday from her home north of Sacramento. “The only memories I really have are mainly at night. You could hear the swooshing of all the iron lungs.”

Lane’s family moved to Northern California a few years after her bout with polio, when she was 8. “That’s when I started noticing I was different than other kids,” she said. “I was in leg braces and had to learn to walk all over again.”

Her parents took her to Shriners Hospital in San Francisco, where she lived on and off for the next eight years.

“It was kind of like a boarding school, except with surgeries,” Lane said. “They did all these muscle and tendon transfers. I think I had maybe 15 to 18 surgeries. They transferred my quads from the front to the back so I could stand.”

In her early 40s, Lane was diagnosed with post-polio syndrome, which afflicts between 25% and 40% of childhood polio survivors. It is similar to chronic fatigue syndrome and can range from mild to debilitating.

“I’m not in a wheelchair yet,” said Lane, who uses leg braces and crutches, “but it’s heading that way.”

The idea that anyone would question the polio vaccine now, she said, “makes me nuts.”

Last week, the New York Times reported that in 2022, Robert F. Kennedy Jr.’s attorney and close advisor Aaron Siri had petitioned the Food and Drug Administration to revoke approval of the polio vaccine in use for the last three decades until its safety can be studied further against an unvaccinated control group. Kennedy, President-elect Donald Trump’s pick for Health and Human Services secretary, is a longtime vaccine skeptic who spouts nonsense about the safety and efficacy of vaccines and a lot of other things. He is, in the view of many medical professionals, a danger to public health.

The Times’ report set off shock waves. Before Jonas Salk developed the first successful polio vaccine in the mid-1950s, the disease killed or paralyzed more than half a million people around the world each year. Many high-profile Americans who suffered from childhood polio, including Senate Republican leader Mitch McConnell and the actor Mia Farrow, immediately condemned the questioning of the vaccine. Kennedy and Trump were forced to reassure Americans that they support the lifesaving treatment.

As Kennedy met with Republican senators to shore up support for his nomination this week, he told reporters that he is “all for” the polio vaccine. Trump, in his first post-election press conference, insisted, “You’re not going to lose the polio vaccine. It’s not going to happen.”

And yet Trump also persisted in promulgating the oft-debunked lie that childhood vaccines are linked to autism, vowing to “look into” the conspiracy theory. Kennedy, he said, will “come back with a report as to what he thinks. We’re going to find out a lot.”

This fear-mongering is unconscionable. We already know a lot. In fact, we know more than a lot.

The autism question has “been studied to death in some ways,” said Richard Pan, a pediatrician and former California state senator who led the successful 2015 campaign to eliminate a “personal belief” exemption from vaccine requirements for the state’s schoolchildren.

“Do we know what causes autism? Not yet,” Pan said. But, he added, we do know what does not cause autism: the measles, mumps and rubella vaccine, which was implicated in a long-since-discredited 1998 paper based on 12 cases by the defrocked English physician Andrew Wakefield.

“What will it take to convince Trump and RFK Jr. that a retracted 12-subject study with fake data was actually wrong?” asked Pan.

In any case, he added, blaming the vaccine is an “ableist” response to autism by some parents. “They don’t want to accept that their child is neurodivergent,” Pan said. “You want to say your child is broken and my life has been ruined and it’s the fault of Big Pharma or whoever.”

People who do not vaccinate their children, he said, are risking the health of the very people they are supposed to protect.

“You are playing with your children’s lives,” he said. “All of these adults have already been vaccinated.”

Although polio has essentially been eradicated in the U.S., it still exists in parts of the world and could certainly make a comeback here if enough people refuse to vaccinate their children. In 2022, the Centers for Disease Control and Prevention reported that an unvaccinated New York man had contracted polio. And earlier this year, amid Israel’s war on Hamas, a 10-month-old child in Gaza contracted the virus, confirming fears about the war’s potential effect on preventable childhood disease.

As for the Kennedy advisor’s petition, Pan said, how could we withhold a potentially lifesaving treatment from children in a control group to test the efficacy of a vaccine that has been used successfully for decades?

“Sometimes a trial cannot be done safely or ethically, “ he said. “Are you willing to volunteer your child into the control group?”

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Three men sought help at clinics or emergency rooms in Los Angeles County over a three-month period this year, each reporting severe diarrhea and a recent history of sexual contact with other men.

Stool cultures revealed that all three were infected with Shigella sonnei, a strain of Shigella bacteria that is resistant to five of the antibiotic classes most commonly prescribed for such infections. But upon further analysis, the UCLA researchers analyzing the samples realized they were looking at something altogether new.

All three cases had a distinct genetic mutation that made the bacteria resistant to yet another class of antibiotics, the cephalosporins, which are often used to treat Shigella infections when other drugs fail.

The strain appears to be unique to Los Angeles and has not been recorded anywhere else, said Dr. Shangxin Yang, a UCLA molecular biologist and clinical microbiologist who is a co-author of the paper describing the find. Although all the patients ultimately recovered, the mutation represents an unsettling new development in a battle against a tiny but hardy foe.

“It’s very alarming,” Yang said. “We are dealing with a very stealthy pathogen, and it’s really successful in spreading in a community.”

Two years ago, the U.S. Centers for Disease Control began tracking a sharp rise in cases of extensively drug-resistant (XDR) shigellosis — infections by particular strains of Shigella bacteria that are impervious to most antibiotics.

The Los Angeles County Department of Public Health reported 45 cases of XDR shigellosis in 2023, up from just five in 2021. The antibiotic-resistant infection causes diarrhea, nausea and stomach cramping and is spreading primarily among men who have sex with other men.

The number of cases detected this year declined somewhat from the 2023 peak, with 30 such infections reported in the county.

But Shigella sonnei, the parent strain of the new ultra-resistant bug discovered at UCLA, remains a tricky pathogen for multiple reasons, Yang said.

For one, many infections are either asymptomatic or relatively mild, allowing people to pass the disease to others without realizing they are sick.

It’s a tough bacteria to grow in the lab, which makes it harder for pathologists to identify which particular strain they’re dealing with, he added. And without being able to identify which bacteria is sickening the patient and prescribe the appropriate treatment, the duration of the infection — and period in which it can be spread to other people — is prolonged.

“What we found is probably only a fraction of what’s really in the community,” Yang said.

Most shigellosis patients, even those infected with drug-resistant strains, will get better on their own without a need for antibiotics, said Dr. Daniel Uslan, an infectious disease specialist at UCLA and a co-author of the paper.

But for patients with compromised immune systems, these infections can lead to serious complications that can’t be easily cured. One of the three patients identified in the recent paper, a 62-year-old man with a history of HIV/AIDS and hepatitis C, was ill enough to be admitted to the intensive care unit with septic shock. He was ultimately treated successfully with meropenem, an antibiotic used sparingly as a last line of defense against infections resistant to other medications.

“This is not a cause for panic. It’s a cause for caution and alarm,” Uslan said.

More broadly, the appearance of a new drug-resistant bacteria is a troubling development in the fight against “superbugs,” or pathogens resistant to most available antibiotics.

A study in the medical journal Lancet this year found that without new medications, “superbug” infections could kill nearly 2 million people a year in 2050 — a 67.5% increase from the 1.14 million lives lost this way in 2021.

An additional 8.22 million will die of causes related to those infections in 2050, according to a study from the Global Research on Antimicrobial Resistance Project.

In June, the World Health Organization warned that far too few new antibiotics are in the global development pipeline, and the ones that are there fall far short of the innovation required to vanquish the most dangerous microbes.

“The discovery of any extensively antibiotic-resistant bacteria is alarming, especially in cities like Los Angeles,” said Henry Skinner, chief executive of the AMR Action Fund, which invests in antimicrobial drugs.

“The bacterium detailed in this report is resistant to some of our most widely used antibiotics, including ciprofloxacin and azithromycin — medicines that tens of thousands of patients depend on daily,” he said. “With so few new antibiotics in development, it’s very concerning to learn that an XDR strain of Shigella may be gaining a foothold in the U.S.”