The number of people living with obesity worldwide has surpassed one billion, according to a global analysis.

Research published by the journal The Lancet suggests that as of 2022, around 159 million children and adolescents and 879 million adults are obese.

In the UK, around 16.8 million people are living with obesity – which includes eight million women, 7.4 million men, 760,000 boys and 590,000 girls.

Data showed that globally, obesity rates among children and adolescents quadrupled from 1990 to 2022, while rates among adults more than doubled.

Meanwhile, the study also revealed over the same period, rates of underweight dropped among children and adolescents and more than halved among adults worldwide.

This makes obesity the most common form of malnutrition in many countries, the researchers said.

Senior author Professor Majid Ezzati, of Imperial College London, said: “It is very concerning that the epidemic of obesity that was evident among adults in much of the world in 1990 is now mirrored in school-aged children and adolescents.

“At the same time, hundreds of millions are still affected by undernutrition, particularly in some of the poorest parts of the world.

“To successfully tackle both forms of malnutrition it is vital we significantly improve the availability and affordability of healthy, nutritious foods.”

In the UK, the obesity rate among adults increased from 13.8% in 1990 to 28.3% in 2022 for women and 10.7% to 26.9% in 2022 for men.

For children and adolescents, the rate jumped from 4.7% in 1990 to 10.1% in 2022 for girls and 4.3% to 12.4% in 2022 for boys.

Meanwhile globally, the obesity rate more than doubled in women, nearly tripled in men, and more than quadrupled in girls and boys, from 1990 to 2022.

Places with the highest prevalence of obesity include Tonga, American Samoa, Polynesia and Micronesia, Cook Islands and Niue.

Data also showed around that globally, as of 2022, around 532 million people are underweight, including 183 million women, 164 million men, 77 million girls and 108 million boys.

And in the UK, around 981,000 people are underweight, which includes 430,000 women, 360,000 men, 61,000 girls and 130,000 boys.

The study was conducted by the NCD Risk Factor Collaboration – a network of health scientists around the world – in collaboration with the World Health Organisation (WHO).

The researchers used body mass index (BMI), which is calculated using their weight and height, to understand how obesity and underweight have changed worldwide over three decades.

The team gathered data from more than 3,000 population studies with 222 million people.

The researchers said that although BMI is an imperfect measure for determining the extent of body fat, it is widely recorded in population-based surveys.

Dr Tedros Adhanom Ghebreyesus, director general of the World Health Organisation, said: “This new study highlights the importance of preventing and managing obesity from early life to adulthood, through diet, physical activity and adequate care, as needed.

“Getting back on track to meet the global targets for curbing obesity will take the work of governments and communities, supported by evidence-based policies from WHO and national public health agencies.

“Importantly, it requires the co-operation of the private sector, which must be accountable for the health impacts of their products.”

Professor Simon Kenny, NHS England’s national clinical director for children and young people, said: “These figures will be as alarming to parents as they are to the NHS.

“Obesity affects every human organ system, and so at a young age can have a major impact on a child’s life, increasing their risk of type 2 diabetes, cancer, mental health issues and many other illnesses, which can lead to shorter and unhappier lives.

“The NHS is committed to helping as many young people and families affected by extreme weight issues as possible through our new network of 30 specialist clinics, which offer tailored packages of physical, psychological and social support – but the NHS cannot solve this issue alone, and continued joined-up action by industry and wider society is needed if we are to avoid a ticking health timebomb for the future.”