Why are more and more people facing the problem of obesity?

Editor's note: World Obesity Day 2025 highlights the urgent need for systemic change to tackle the obesity crisis. China has stepped up policy efforts to boost public awareness and set up standardized clinical guidelines for obesity diagnosis and treatment. Dr Zhang Peng, director of metabolic and bariatric surgery at Capital Medical University Beijing Friendship Hospital and a leading contributor to China's latest national obesity diagnosis and treatment guidelines, offers insights into the reasons for the obesity crisis and the growing pressures on healthcare systems.

The global obesity crisis has become one of the most pressing public health challenges of the 21st century.

According to 2022 data from the World Health Organization, over one billion people worldwide – roughly one in eight individuals – are now living with obesity. The number continues to rise and is predicted to reach 1.9 billion by 2035.

Obesity is a leading risk factor for non-communicable diseases, including type 2 diabetes, cardiovascular diseases and certain cancers. The World Obesity Federation warns that obesity-related illnesses could cost the global economy $4 trillion annually by 2035.

In China, over 50 percent of adults were overweight or obese as of 2020 data, totaling a staggering 600 million people – the highest figure globally. 

Body mass index (BMI) is a common indicator to assess if a person's weight is healthy for their height. It is calculated by dividing weight (kg) by height squared (m²). In China, a BMI of 24.0-27.9 kg/m² is deemed overweight, and 28.0 kg/m² or above is obese.

"If all these people were to seek treatment at hospitals, it would pose a significant challenge to the healthcare system," said Dr Zhang Peng, director of metabolic and bariatric surgery at Beijing Friendship Hospital.

"Projections indicate that by 2030, 22 percent of the country's healthcare expenditures will be linked to obesity," he added. 

Drivers of the crisis

"Obesity can stem from a variety of factors, including family clustering of obesity, stress-related eating, a sedentary lifestyle, high-calorie food choices and the traditional perception associating excess weight with wealth," said Zhang.

Zhang noted that certain hormonal medications, underlying diseases and genetic mutations can also lead to obesity, but this kind of secondary obesity is relatively rare.

The drivers of the crisis vary across different regions, and addressing it requires multisectoral actions, including rethinking food production and the healthcare system. Zhang emphasized that obesity prevention measures need to be deeply integrated into communities.

"We must guide the public to adopt a healthy lifestyle to prevent obesity, help those who have already gained weight to avoid developing diseases and encourage those who have developed diseases due to obesity to actively seek medical treatment," he added.

Responses in China

China has ramped up efforts to combat the obesity crisis in recent years through a multifaceted approach blending top-down policy, healthcare innovation and cultural shifts.

Under Healthy China 2030, a national health blueprint published in 2016, the country prioritized obesity prevention by promoting improved nutrition, physical activity and public education. Key targets include halting the rise in obesity rates among children and adolescents by 2030. 

In 2019, a follow-up plan detailing the full implementation and evaluation of the blueprint was released, providing technological support through expert teams and outlining key tasks.

China has also updated its dietary guidelines to emphasize reduced intake of salt, oil and sugar, while encouraging greater consumption of whole grains, vegetables and plant-based proteins. 

To boost physical activity, the government has expanded public sports infrastructure. As of the end of 2023, there were a total of 4.6 million sports venues in China, with an average of 2.9 square meters of sports venue area per person. 

For childhood obesity, China has introduced strict measures, including restrictions on junk food advertising to children and bans on high-sugar snack sales in schools. Students are now required to exercise for at least one hour daily during school hours.

With obesity rates surging, many public hospitals have opened specialized obesity clinics to meet the growing demand for medical interventions. Additionally, China has released multiple clinical guidelines to standardize obesity diagnosis and treatment, as well as to establish multidisciplinary care pathways.

Challenges ahead

Zhang stated that the 2024 National Obesity Diagnosis and Treatment Guideline establishes detailed grading criteria for diagnosis and treatment, including lifestyle interventions, medication and surgical options.

"We increasingly recognize the critical role of multidisciplinary collaboration in obesity treatment. At the same time, doctors must shift their mindset and work with patients to develop personalized plans, which should be based upon shared decision-making between physicians and patients – only those that patients can adhere to will be effective," he explained.

Zhang highlighted systemic gaps in China's healthcare approach.

"A key issue is the lack of specialized obesity training. Medical schools and residency programs do not offer dedicated courses and programs, leading to inconsistent advice from doctors," Zhang said.

"In hospitals, multiple departments run their own weight-loss clinics without a unified strategy. Patients receive conflicting treatment plans, leaving them unsure whose advice to follow," he added.

He also noted that obesity-related stigma often originates within families, where overweight members face open criticism.

"Overweight students may face discrimination from teachers and peers, particularly if they struggle academically. These students need support, not judgment," he said.

(Cover via VCG; graphics by Sun Yiwen, Zhu Shangfan)