Lack of exercise along with sugar-sweetened foods and drinks have caused one out of six five-year-olds in Sweden to be overweight or obese. The breakdown is 12.9% of children are considered overweight and 4.3% are considered obese.

According to 2007 statistics from the World Health Organization (WHO), Australia has the third-highest prevalence of overweight adults in the English-speaking world.Obesity in Australia is an "epidemic" with "increasing frequency." "The Medical Journal of Australia" found that obesity in Australia more than doubled in the two decades preceding 2003, and the unprecedented rise in obesity has been compared to the same health crisis in America. The rise in obesity has been attributed to poor eating habits in the country closely related to the availability of fast food since the 1970s, sedentary lifestyles and a decrease in the labour workforce.

The first problems to occur in obese children are usually emotional or psychological. Obese children often experience bullying by their peers. Some are harassed or discriminated against by their own family. Stereotypes abound and may lead to low self-esteem and depression.

Obesity in Greece is a growing health concern with health officials stating that it is one of the leading causes of preventable deaths in Greece.

The degree to which a person is overweight is generally described by the body mass index (BMI). "Overweight" is defined as a BMI of 25 or more, thus it includes pre-obesity defined as a BMI between 25 and 30 and obesity as defined by a BMI of 30 or more. Pre-obese and overweight however are often used interchangeably, thus giving overweight a common definition of a BMI of between 25–30. There are, however, several other common ways to measure the amount of adiposity or fat present in an individual's body.

- Body mass index

- Body volume index

- Simple weighing

- Skinfold calipers or "pinch test"

- Bioelectrical impedance analysis

- Hydrostatic weighing

- Dual-energy X-ray absorptiometry (DEXA)

The most common method for discussing this subject and the one used primarily by researchers and advisory institutions is BMI. Definitions of what is considered overweight vary by ethnicity. The current definition proposed by the US National Institutes of Health (NIH) and the World Health Organization (WHO) designates whites, Hispanics and blacks with a BMI of 25 or more as overweight. For Asians, overweight is a BMI between 23 and 29.9 and obesity for all groups is a BMI of 30 or more.

BMI, however, does not account extremes of muscle mass, some rare genetic factors, the very young, and a few other individual variations. Thus it is possible for an individuals with a BMI of less than 25 to have excess body fat, while others may have a BMI that is significantly higher without falling into this category. Some of the above methods for determining body fat are more accurate than BMI but come with added complexity.

If an individual is overweight and has excess body fat it can create or lead to health risks. Reports are surfacing, however, that being mildly overweight to slightly obese – BMI being between 24 and 31.9 – may be actually beneficial and that people with a BMI between 24 and 31.9 could actually live longer than normal weight or underweight persons.

Obesity in Sweden has been increasingly cited as a major health issue in recent years. Sweden is the 90th fattest country in the world. In 2009, the number of people who are considered obese and overweight had not increased for the first time in 70 years. Claude Marcus, a leading Swedish nutrition expert from the Karolinska Institutet, stated that one solution is to introduce a fat tax. Folksam refused to insure a 5-year-old girl from Orust. The insurance company refused her insurance based on "serious overweight/obesity". A report showed that children whose parents were better educated had a lower chance of becoming fat.

Body mass index (BMI) is acceptable for determining obesity for children two years of age and older. It is determined by the ratio of weight to height.

The normal range for BMI in children vary with age and sex. While a BMI above the 85th percentile is defined as overweight, a BMI greater than or equal to the 95th percentile is defined as obesity by Centers for Disease Control and Prevention. It has published tables for determining this in children.

The US Preventive Service Task Force reported that not all children with a high BMI need to lose weight though. High BMI can identify a possible weight problem, but does not differentiate between fat or lean tissue. Additionally, BMI may mistakenly rule out some children who do have excess adipose tissue. It is therefore beneficial to supplement the reliability of a BMI diagnosis with additional screening tools such as adipose tissue or skin fold measurements.

Obesity in North Africa and the Middle East is a notable health issue. In 2005, the World Health Organization measured that 1.6 billion people were overweight and 400 million were obese. It estimates that by the year 2015, 2.3 billion people will be overweight and 700 million will be obese. The Middle East, including the Arabian Peninsula, Eastern Mediterranean, Turkey and Iran, and North Africa, are no exception to the worldwide increase in obesity. Subsequently, some call this trend the New World Syndrome. The lifestyle changes associated with the discovery of oil and the subsequent increase in wealth is one contributing factor.

Urbanization has occurred rapidly and has been accompanied by new technologies that promote sedentary lifestyles. Due to accessibility of private cars, television, and household appliances, the population as a whole is engaging in less physical activity. The rise in caloric and fat intake in a region where exercise is not a defining part of the culture has added to the overall increased percentages of overweight and obese populations. In addition, women are more likely to be overweight or obese due to cultural norms and perceptions of appropriate female behavior and occupations inside and outside of the home.

Obesity in Mexico is a relatively recent phenomenon, having been widespread since the 1980s with the introduction of processed food into much of the Mexican food market. Prior to that, dietary issues were limited to under and malnutrition, which is still a problem in various parts of the country. Following trends already ongoing in other parts of the world, Mexicans have been foregoing traditional whole grains and vegetables in favor of a diet with more animal products, more fat, and more sugar much of which is a consequence of processed food. It has seen dietary energy intake and rates of overweight and obese people rise with seven out of ten at least overweight and a third clinically obese.

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health. It is defined by body mass index (BMI) and further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. BMI is closely related to both percentage body fat and total body fat.

In children, a healthy weight varies with age and sex. Obesity in children and adolescents is defined not as an absolute number but in relation to a historical normal group, such that obesity is a BMI greater than the 95th percentile. The reference data on which these percentiles were based date from 1963 to 1994, and thus have not been affected by the recent increases in weight. BMI is defined as the subject's weight divided by the square of their height and is calculated as follows.

BMI is usually expressed in kilograms per square metre, resulting when weight is measured in kilograms and height in metres. To convert from pounds per square inch multiply by .

The most commonly used definitions, established by the World Health Organization (WHO) in 1997 and published in 2000, provide the values listed in the table.

Some modifications to the WHO definitions have been made by particular organizations. The surgical literature breaks down class II and III obesity into further categories whose exact values are still disputed.

- Any BMI ≥ 35 or 40 kg/m is "severe obesity".

- A BMI of ≥ 35 kg/m and experiencing obesity-related health conditions or ≥40–44.9 kg/m is "morbid obesity".

- A BMI of ≥ 45 or 50 kg/m is "super obesity".

As Asian populations develop negative health consequences at a lower BMI than Caucasians, some nations have redefined obesity; Japan have defined obesity as any BMI greater than 25 kg/m while China uses a BMI of greater than 28 kg/m.

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health. People are generally considered obese when their body mass index (BMI), a measurement obtained by dividing a person's weight by the square of the person's height, is over , with the range defined as overweight. Some East Asian countries use lower values. Obesity increases the likelihood of various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, osteoarthritis and depression.

Obesity is most commonly caused by a combination of excessive food intake, lack of physical activity, and genetic susceptibility. A few cases are caused primarily by genes, endocrine disorders, medications, or mental disorder. The view that obese people eat little yet gain weight due to a slow metabolism is not generally supported. On average, obese people have a greater energy expenditure than their normal counterparts due to the energy required to maintain an increased body mass.

Obesity is mostly preventable through a combination of social changes and personal choices. Changes to diet and exercising are the main treatments. Diet quality can be improved by reducing the consumption of energy-dense foods, such as those high in fat and sugars, and by increasing the intake of dietary fiber. Medications may be used, along with a suitable diet, to reduce appetite or decrease fat absorption. If diet, exercise, and medication are not effective, a gastric balloon or surgery may be performed to reduce stomach volume or length of the intestines, leading to feeling full earlier or a reduced ability to absorb nutrients from food.

Obesity is a leading preventable cause of death worldwide, with increasing rates in adults and children. In 2015, 600 million adults (12%) and 100 million children were obese. Obesity is more common in women than men. Authorities view it as one of the most serious public health problems of the 21st century. Obesity is stigmatized in much of the modern world (particularly in the Western world), though it was seen as a symbol of wealth and fertility at other times in history and still is in some parts of the world. In 2013, the American Medical Association classified obesity as a disease.

Obesity in Germany has been increasingly cited as a major health issue in recent years. The federal government has declared this to be a major issue.

Data released by the World Health Organisation in 2014 showed that while an issue of growing concern, within the European Union, Germany had a lower incidence of overweight and obese adults as a percentage of the total population at 54.8% in comparison with France at 60.7%, Spain at 60.9% or the United Kingdom at 63.4%.

Obesity has been observed throughout human history. Many early depictions of the human form in art and sculpture appear obese. However, it was not until the 20th century that obesity became common — so much so that, in 1997, the World Health Organization (WHO) formally recognized obesity as a global epidemic. Obesity is defined as having a body mass index (BMI) greater than or equal to 30 kg/m, and in June 2013 the American Medical Association classified it as a disease, with much controversy.

In countries of the Organisation for Economic Co-operation and Development (OECD), one child out of five is overweight or obese. Once considered a problem only of high-income countries, obesity rates are rising worldwide. Globally, there are now more people who are obese than who are underweight, a trend observed in every region over the world except parts of sub-Saharan Africa and Asia. In 2013, an estimated 2.1 billion adults were overweight, as compared with 857 million in 1980. Of adults who are overweight, 31% are obese. Increases in obesity have been seen most in urban settings.

Since body fat can be measured in several ways, statistics on the epidemiology of obesity vary between sources. While BMI is the most basic and commonly used indicator of obesity, other measures include waist circumference, waist-to-hip ratio, skinfold thicknesses, and bioelectrical impedance. The rate of obesity increases with age at least up to 50 or 60 years old.

The OECD notes that — given the health, economic, and social consequences of obesity — many countries have built multi-stakeholder networks involving civil society and the business sector in order to devise appropriate public health policies and solutions for obesity prevention.

The percentage of overweight Ukrainians is at 53% of the population and the percentage of Ukrainians who meet the definition of obese is 20%. Statistics show that Ukrainians continue to gain weight. Doctors claim that the regions with the ""thickest Ukrainians"" are Donetsk and Poltava regions. Crimea is considered ""the most slender region of the country"" The percentage of overweight people in Crimea is 49,7% and the percentage of people who meet the definition of obesity is 12,3%.

Obesity in India has reached epidemic proportions in the 21st century, with morbid obesity affecting 5% of the country's population. India is following a trend of other developing countries that are steadily becoming more obese. Unhealthy, processed food has become much more accessible following India's continued integration in global food markets. This, combined with rising middle class incomes, is increasing the average caloric intake per individual among the middle class and above income households. Obesity is a major risk factor for cardiovascular disease, NGOs such as the Indian Heart Association have been raising awareness about this issue.

While studying 22 different SNPs near to MC-R gene, scientists have identified a SNP (single nucleotide polymorphism) named rs12970134 to be mostly associated with waist circumference. In this study more than two thousand individuals of Indian origin participated and the aforementioned SNP is highly prevalent in this group.

Internationally, a BMI over 25 kg/m2 is considered overweight. Due to genetic tendency of Indians towards abdominal obesity and its associated risk of related lifestyle diseases like Diabetes & Heart Disease, Guidelines for diagnosis of obesity and abdominal obesity for India have been published in JAPI (2009) that a BMI over 23 kg/m2 is considered overweight. Further definitions: Normal BMI: 18.0-22.9 kg/m2, Overweight: 23.0-24.9 kg/m2, Obesity: >25 kg/m2.

Being overweight is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.

Excess weight has reached epidemic proportions globally, with more than 1 billion adults being either overweight or obese in 2003. In 2013 this increased to more than 2 billion. Increases have been observed across all age groups.

A healthy body requires a minimum amount of fat for proper functioning of the hormonal, reproductive, and immune systems, as thermal insulation, as shock absorption for sensitive areas, and as energy for future use. But the accumulation of too much storage fat can impair movement, flexibility, and alter the appearance of the body.

Until the late 20th century, dietary issues in Mexico were solely a question of undernutrition or malnutrition, generally because of poverty and distribution issues. For this reason, obesity was associated with wealth and health, the latter especially in children. Despite changes in the Mexican diet and food distribution, malnutrition still remains problematic in various parts of the country.

Obesity in Canada is a growing health concern, which is "expected to surpass smoking as the leading cause of preventable morbidity and mortality … and represents a burden of Can$3.96 (US$3.04/€2.75) billion on the Canadian economy each year."

Obesity is defined as the excessive accumulation of fat and is predominately caused when there is an energy imbalance between calorie consumption and calorie expenditure. Childhood obesity is becoming an increasing concern worldwide and Australia alone, recognizes that 1 in 4 children are either overweight or obese.

For Australians aged between 4 and 17 years, obesity is a very concerning condition as once gained it is favourably harder to be liberated from. Short-term effects on children can mean a decrease in their psychological well-being (stigmatisation and poor self-esteem) as well as physical deteriorations such as sleep apnea, breathlessness and cardiovascular disease. With an increase risk of adult obesity being associated with childhood obesity there are numerous long-term effects that can ultimately hinder the life expectancy of individuals including the development of serious diseases.

In order to combat the worldwide epidemic of childhood obesity it is imperative that the issue is addressed in its early stages. The main preventative measures to be implemented include increasing physical exercise, dietary knowledge and decreasing sedentary behaviours.

Obesity in Ukraine is a health issue in Ukraine. Overall, 53% are considered overweight and 20% meet the definition of obesity. The Donetsk and Poltava regions are considered the ""thickest"(most overweight) and Crimea is considered to have the least number of fat people. The lack of a healthy diet has been cited as a cause of obesity.

Obesity in Nauru is a major health concern for the nation. In 2007 Forbes.com reported that, according to the World Health Organization's (WHO) latest estimate, Nauru has the highest percentage of overweight inhabitants among all countries. The estimation identified 94.5% of its residents as overweight. The obesity rate is 71.7%, the highest in the world. The definition of "overweight" and "obesity" are based on body mass index (BMI). People with BMI more than or equal to 25 are classified as overweight, and people with BMI more than or equal to 30 are classified as obese.

The average body weight among Nauruans is estimated to be approximately . Nauru has an average BMI between 34 and 35.

The medical condition of being overweight or obesity is defined as "abnormal or excessive fat accumulation that may impair health". It is measured through the Body Mass Index (BMI), defined as a person's weight, in kilograms, divided by the square of the person's height, in meters. If an individual has a BMI of 25–29, he or she is overweight. Having a BMI of 30 or more means an individual is obese. The greater the BMI, the greater the risk of chronic diseases as a result of obesity. These diseases include cardiovascular diseases, diabetes, musculoskeletal disorders, cancer, and premature death.

Obesity in Austria has been increasingly cited as a major health issue in recent years. Forty per cent of Austrians between 18 and 65 are considered overweight while eleven per cent of those overweight meet the definition of obesity. Forbes.com ranks Austria as the 52nd fattest country in the World with a rate of 57.1%. Approximately 900,000 people are considered overweight or obese.

Obesity in Pakistan is a health issue that has attracted concern only in the past few years. Urbanisation and an unhealthy, energy-dense diet (the high presence of oil and fats in Pakistani cooking), as well as changing lifestyles, are among the root causes contributing to obesity in the country. According to a list of the world's "fattest countries" published on "Forbes", Pakistan is ranked 165 (out of 194 countries) in terms of its overweight population, with 22.2% of individuals over the age of 15 crossing the threshold of obesity. This ratio roughly corresponds with other studies, which state one-in-four Pakistani adults as being overweight.

Research indicates that people living in large cities in Pakistan are more exposed to the risks of obesity as compared to those in the rural countryside. Women also naturally have higher rates of obesity as compared to men. Pakistan also has the highest percentage of people with diabetes in South Asia.

According to one study, "fat" is more dangerous for South Asians than for Caucasians because the fat tends to cling to organs like the liver instead of the skin.

Obesity in France is a growing health issue. Obesity in children is growing at a faster rate than obesity in adults.

Based on World Health Organisation (WHO) data published in 2014, 23.9% of French adults (age 18+) were clinically obese with a body mass index (BMI) of 30 or greater. The data showed the incidence of obesity in French women in 2014 was 24.0% and among French men 23.8%. Overall adult obesity rates in France were significantly ahead of the Netherlands at 19.8%, Germany at 20.1% and Italy at 21.0%, but behind the United Kingdom and the United States at 28.1% and 33.7% respectively.

Based on 2014 WHO data, France was ranked as the 122nd fattest country in terms of mean BMI for adults of both sexes, with a mean BMI score of 25.3.