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Obesity

Overweight and obesity are defined as abnormal or excessive accumulations of body fat that can put a person’s health at risk.

Global estimates suggest that almost 2.3 billion children and adults are overweight.

If current trends continue, 2.7 billion adults could be overweight or obese by 2025.

Obesity is a major public health challenge that affects almost every country in the world. Globally, obesity rates have been increasing steadily over the last three decades. In almost every region, there are now more people living with obesity than underweight, and if current numbers continue to rise, as many as 1 billion adults, or 12% of the world population, will be living with obesity by 2025.

Once considered exclusively a high-income country problem, today obesity is an issue of growing concern in many low- and middle-income countries, particularly among children. Asia and Africa are home to nearly three-quarters of all overweight children worldwide. In Africa, the number of overweight children under 5 has increased by nearly 24% since 2000, and almost half of the children under 5 who were overweight or obese in 2019 live in Asia.

13%

of the global adult population is living with obesity

3 BILLION

people lack access to healthy food

17%

of CVD deaths are linked to obesity

Obesity is a key risk factor for cardiovascular disease that can affect people of all ages and socioeconomic backgrounds. It can lead to a range of health issues, including cardiovascular disease, diabetes, kidney disease and neoplasms. It can also have serious social and psychological consequences for those affected. Public health initiatives that target obesity can therefore help mitigate the impact of a wide range of diseases and conditions.

Despite being one of the most important public health problems facing the world today, obesity remains worryingly neglected in many parts of the world.

The World Health Organization defines overweight and obesity as “abnormal or excessive fat accumulation that presents a risk to health”. It can be measured and identified in a number of ways, but the most widely used method is Body Mass Index (BMI), which uses a person’s height and weight to calculate whether their weight is healthy. BMI is defined as a person’s weight in kilograms divided by the square of their height in meters. In adults, a BMI over 25 is considered overweight, and over 30 is obese.

BMI applies in the same way for adults of all sexes and ages, and is therefore the most useful population-level measure of overweight and obesity. However, it should be considered a rough guide because it may not correspond to the same degree of overweight in different individuals.

BMI Classification
18.5-24.99 – Healthy Weight
≥25.00 – Overweight
≥30.00 – Obese
≥40.00 – Severely Obese

The fundamental cause of obesity is an imbalance between calories consumed and calories expended. The body gains fat when it stores excess energy, and this excess energy is formed when we consume more calories than we burn.

This imbalance in energy consumption and expenditure may have several causes, including genetic disorders, but in most cases it results from living in an environment that allows and encourages low levels of physical activity, prolonged sedentary behaviour and the excess consumption of energy-rich foods.

The growing availability of ultra-processed foods, which contain high levels of sugars, sodium, saturated fats and refined carbohydrates, is a key contributor to the current obesity epidemic.

As global diets have changed in recent decades, there has been an increase in the consumption of foods that are high in fat and free sugars. There has also been an increase in physical inactivity due to the increasingly sedentary nature of many types of work, changing modes of transportation and increased urbanization.

These changes in dietary and physical activity patterns are often the result of environmental and societal changes associated with development and lack of supportive policies in sectors such as health, agriculture, transport, urban planning, environment, food processing, distribution, marketing, and education.

While unhealthy diet and lack of physical activity are key risk factors for obesity, individual choice is not the only factor to determine a person’s risk of obesity. It’s also not the only factor to determine a person’s diet and how active they are.

Simply telling people to eat healthier and exercise more will not solve the obesity crisis, because obesity is often driven by forces outside our control, including biological, social, economic and environmental factors. A person’s biology and genes can put them at greater risk of obesity; their income and where they live can impact their access to healthy food, suitable medical care and opportunities for a healthy, active life; their environment and life experiences can also affect their mental and emotional health, which can in turn increase a person’s risk of obesity.

According to the United Nations Food and Agriculture Organization, healthy diets continue to be out of reach for as many as three billion people worldwide, due to the high cost of healthy diets and persistent high levels of income inequality.

In many countries, people living with obesity are regularly blamed for their disease. Weight stigma suggests that obesity is due to individual failure and puts responsibility on people living with obesity to fix the problem. This can damage mental and physical wellbeing and prevent people from seeking necessary medical care.

Overweight and obesity are major risk factors for a wide range of noncommunicable diseases (NCDs), including:

  • cardiovascular disease
  • diabetes
  • hypertension
  • musculoskeletal disorders and back pain
  • some forms of cancer (endometrial, breast, ovarian, prostate, liver, gallbladder, kidney, and colon)
  • liver disorders
  • mental health-related conditions

The risk of these conditions usually increases with BMI.

In both children and adults, obesity can also lead to social stigma and isolation, reduced attendance at school and difficulties in finding and keeping a job.

Childhood obesity is associated with a wide range of serious health complications and an increased risk of premature onset of related illnesses. It can have a profound effect a child’s physical, social and emotional wellbeing. Children with obesity are at higher risk of experiencing:

  • breathing difficulties
  • increased risk of fractures
  • hypertension
  • metabolic disorders
  • early markers of cardiovascular disease
  • insulin resistance
  • low self-esteem
  • other psychological effects

Childhood obesity is also associated with a higher risk of obesity, premature death and disability in adulthood, so preventing and treating it is vital to stopping the global obesity epidemic.

Overweight and obesity are largely preventable and reversible.

It the individual level, lowering your risk of overweight and obesity normally involves reducing the number of calories consumed from fats and sugars, increasing your daily intake of fruit, vegetables, whole grains and nuts, and exercising regularly. At least 60 minutes of exercise most days a week will help you maintain a healthy body weight.

Eating a healthy and balanced diet

Eating a healthy, balanced diet is crucial to maintaining a healthy heart and circulation system. A healthy diet should include a wide variety of unprocessed and fresh foods, including plenty of fruit and vegetables (at least five portions every day), whole grains, nuts and foods low in saturated fats, sugars and salt. Be wary of processed foods, which often contain high levels of salt, and drink lots of water!

Exercising regularly

It only takes 30 minutes of moderate-intensity physical activity, five days a week, to improve and maintain your health. Adults (aged 18-65) and seniors (65+) should aim to do at least 150 minutes of moderate-intensity physical activity, or at least 75 minutes of high-intensity physical activity, every week. Children and adolescents should do at least 60 minutes of moderate- to vigorous-intensity physical activity every day.

Try to make exercise a regular part of your life: use the stairs instead of the lift, get off the bus a few stops earlier and walk the rest of the way. Being active is also a great way to relieve stress and control your weight, which are both risk factors for cardiovascular disease.

At the government level, policymakers can play an important role in ensuring people have access to the tools they need to lead and active and healthy life. Governments can support individuals to make healthier choices by implementing policies that make regular physical activity and healthier dietary choices available, affordable and easily accessible to everyone, including those with the lowest incomes. Some examples of such policies are:

  • Implementing a mandatory, easy to understand front-of-pack labelling system
  • Restricting the amount of sugar that can be present in food products
  • Implementing a sugar tax
  • Restricting the marketing of junk food to children
  • Developing well-planned urban spaces that encourage and active lifestyle

Creating environments where a healthy diet and regular physical activity are the easiest, most accessible and most affordable choice are essential to motivating people to adopt and sustain healthy lifestyles, and in turn to reducing the global burden of overweight and obesity.

According to the World Health Organization, more than 2 billion people around the world lack regular access to safe, nutritious and sufficient food.

The double burden of malnutrition is the coexistence of undernutrition and overnutrition at all levels of the population. It primarily affects low- and middle-income countries, more than a third of which are experiencing rapidly rising rates of obesity while continuing to deal with the problem of undernutrition, especially in cities and among the poorest and most vulnerable communities.

In order for policies against malnutrition in all its forms to be effective, undernutrition and overnutrition must be understood as two issues that are interconnected. Both are a result of food systems that fail to provide all people with healthy, safe, affordable, and sustainable diets.

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