There are various ways of measuring abdominal obesity including:

- Absolute waist circumference (> in men and > in women)

- Waist–hip ratio (the circumference of the waist divided by that of the hips of >0.9 for men and >0.85 for women)

- Waist-to-height ratio

- Sagittal Abdominal Diameter

In those with a BMI under 35, intra-abdominal body fat is related to negative health outcomes independent of total body fat. Intra-abdominal or visceral fat has a particularly strong correlation with cardiovascular disease.

BMI and waist measurements are well recognized ways to characterize obesity. However, waist measurements are not as accurate as BMI measurements. For this reason, it is recommended to use both methods of measurements.

While central obesity can be obvious just by looking at the naked body (see the picture), the severity of central obesity is determined by taking waist and hip measurements. The absolute waist circumference in men and in women) and the waist-hip ratio (>0.9 for men and >0.85 for women) are both used as measures of central obesity. A differential diagnosis includes distinguishing central obesity from ascites and intestinal bloating. In the cohort of 15,000 people participating in the National Health and Nutrition Examination Survey (NHANES III), waist circumference explained obesity-related health risk better than the body mass index (or BMI) when metabolic syndrome was taken as an outcome measure and this difference was statistically significant. In other words, excessive waist circumference appears to be more of a risk factor for metabolic syndrome than BMI. Another measure of central obesity which has shown superiority to BMI in predicting cardiovascular disease risk is the Index of Central Obesity (waist-to-height ratio - WHtR), where a ratio of >=0.5 (i.e. a waist circumference at least half of the individual's height) is predictive of increased risk.

Another diagnosis of obesity is the analysis of intra-abdominal fat having the most risk to one's personal health. The increased amount of fat in this region relates to the higher levels of plasma lipid and lipoproteins as per studies mentioned by Eric Poehlman (1998) review.

An increasing acceptance of the importance of central obesity within the medical profession as an indicator of health risk has led to new developments in obesity diagnosis such as the Body Volume Index, which measures central obesity by measuring a person's body shape and their weight distribution. The effect of abdominal adiposity occurs not just in those who are obese, but also affects people who are non-obese and it also contributes to insulin sensitivity

Exclusive breast-feeding is recommended in all newborn infants for its nutritional and other beneficial effects. Parents changing the diet and lifestyle of their offspring by offering appropriate food portions, increasing physical activity, and keeping sedentary behaviors at a minimum may also decrease the obesity levels in children.

If children were more mobile and less sedentary, the rate of obesity would decrease. Parents should recognize the signs and encourage their children to be more physically active. By walking or riding a bike, instead of using motorised transport or watching television, will reduce sedentary activity.

Index of Central Obesity (ICO) is the ratio of waist circumference and height first proposed by a Parikh "et al." in 2007 as a better substitute to the widely used waist circumference in defining metabolic syndrome. The National Cholesterol Education Program Adult Treatment Panel III suggested cut off of and for males and females as a marker of central obesity. The same was used in defining metabolic syndrome. Misra et al. suggested that these cutoffs are not applicable among Indians and the cutoffs be lowered to and for males and females. Various race specific cutoffs were suggested by different groups. The International Diabetes Federation defined central obesity based on these various race and gender specific cutoffs. The other limitation of waist circumference is that it can not be applied in children.

Parikh et al. looked at the average heights of various races and suggested that by using ICO various race- and gender-specific cutoffs of waist circumference can be discarded. An ICO cutoff of 0.5 was suggested as a criterion to define central obesity. Parikh "et al." further tested a modified definition of metabolic syndrome in which waist circumference was replaced with ICO in the National Health and Nutrition Examination Survey (NHANES) database and found the modified definition to be more specific and sensitive.

This parameter has been used in the study of metabolic syndrome and cardiovascular disease.

As of 2015 there is not good evidence comparing surgery to lifestyle change for obesity in children. There are a number of high quality ongoing studies looking at this issue.

The term "non-syndromic obesity" is sometimes used to exclude these conditions. In people with early-onset severe obesity (defined by an onset before 10 years of age and body mass index over three standard deviations above normal), 7% harbor a single locus mutation.

Many organizations have published reports pertaining to obesity. In 1998, the first US Federal guidelines were published, titled "Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report". In 2006 the Canadian Obesity Network published the "Canadian Clinical Practice Guidelines (CPG) on the Management and Prevention of Obesity in Adults and Children". This is a comprehensive evidence-based guideline to address the management and prevention of overweight and obesity in adults and children.

In 2004, the United Kingdom Royal College of Physicians, the Faculty of Public Health and the Royal College of Paediatrics and Child Health released the report "Storing up Problems", which highlighted the growing problem of obesity in the UK. The same year, the House of Commons Health Select Committee published its "most comprehensive inquiry [...] ever undertaken" into the impact of obesity on health and society in the UK and possible approaches to the problem. In 2006, the National Institute for Health and Clinical Excellence (NICE) issued a guideline on the diagnosis and management of obesity, as well as policy implications for non-healthcare organizations such as local councils. A 2007 report produced by Derek Wanless for the King's Fund warned that unless further action was taken, obesity had the capacity to cripple the National Health Service financially.

Comprehensive approaches are being looked at to address the rising rates of obesity. The Obesity Policy Action (OPA) framework divides measure into 'upstream' policies, 'midstream' policies, 'downstream' policies. 'Upstream' policies look at changing society, 'midstream' policies try to alter individuals' behavior to prevent obesity, and 'downstream' policies try to treat currently afflicted people.

The main treatment for obesity consists of dieting and physical exercise. Diet programs may produce weight loss over the short term, but maintaining this weight loss is frequently difficult and often requires making exercise and a lower food energy diet a permanent part of a person's lifestyle.

In the short-term low carbohydrate diets appear better than low fat diets for weight loss. In the long term; however, all types of low-carbohydrate and low-fat diets appear equally beneficial. A 2014 review found that the heart disease and diabetes risks associated with different diets appear to be similar. Promotion of the Mediterranean diets among the obese may lower the risk of heart disease. Decreased intake of sweet drinks is also related to weight-loss. Success rates of long-term weight loss maintenance with lifestyle changes are low, ranging from 2–20%. Dietary and lifestyle changes are effective in limiting excessive weight gain in pregnancy and improve outcomes for both the mother and the child. Intensive behavioral counseling is recommended in those who are both obese and have other risk factors for heart disease.

Five medications have evidence for long-term use orlistat, lorcaserin, liraglutide, phentermine–topiramate, and naltrexone–bupropion. They result in weight loss after one year ranged from 3.0 to 6.7 kg over placebo. Orlistat, liraglutide, and naltrexone–bupropion are available in both the United States and Europe, whereas lorcaserin and phentermine–topiramate are available only in the United States. European regulatory authorities rejected the latter two drugs in part because of associations of heart valve problems with lorcaserin and more general heart and blood vessel problems with phentermine–topiramate. Orlistat use is associated with high rates of gastrointestinal side effects and concerns have been raised about negative effects on the kidneys. There is no information on how these drugs affect longer-term complications of obesity such as cardiovascular disease or death.

The most effective treatment for obesity is bariatric surgery. The types of procedures include laparoscopic adjustable gastric banding, Roux-en-Y gastric bypass, vertical-sleeve gastrectomy, and biliopancreatic diversion. Surgery for severe obesity is associated with long-term weight loss, improvement in obesity related conditions, and decreased overall mortality. One study found a weight loss of between 14% and 25% (depending on the type of procedure performed) at 10 years, and a 29% reduction in all cause mortality when compared to standard weight loss measures. Complications occur in about 17% of cases and reoperation is needed in 7% of cases. Due to its cost and risks, researchers are searching for other effective yet less invasive treatments including devices that occupy space in the stomach.

Although there are many short- term preventative methods in place to combat childhood, there are some individuals who return to their initial base weight and therefore might turn to surgical measures to achieve a more lasting effect. Bariatric surgery is an effective procedure used to restrict the patients food intake and decrease absorption of food in the stomach and intestines. Proecdures of this type are said to be able to reduce excess body weight of obese or overweight individuals by 50-75%, ultimately maintaining this weight loss for 16 years following.

The usual treatments for overweight individuals is diet and physical exercise.

Dietitians generally recommend eating several balanced meals dispersed through the day, with a combination of progressive, primarily aerobic, physical exercise.

Because these general treatments help most case of obesity, they are common in all levels of overweight individuals.

As much as 64% of the United States' adult population is considered either overweight or obese, and this percentage has increased over the last four decades.

Body Mass Index (BMI) is a common and useful measurement of body fat that helps individuals understand the difference between being overweight and obese. The system can be used to calculate a persons Body Mass Index (BMI) by dividing their weight (in kilograms) by the square of their height (in meters). According to the World Health Organisation (2015) a BMI greater than or equal to 25 kg/m2 in adults is overweight and greater than or equal to 30 kg/m2 regards individuals as obese. Using the BMI method, however, to measure a child's excess weight can encounter regular issues. The Body Mass Index is used to decipher an individuals excess body weight but not their excess body fat. In this way the measurements taken from a child who is at different stages of their sexual maturation compared to another may alter the reliability of the data. Other issues that may affect the results surrounding this method for children and adolescents includes their age, sex, ethnicity muscle and bone mass, their height as well as their sexual maturation levels. Using the percentile ranking to determine whether or not a child or adolescent between 2–20 years old is overweight or obese inherits the same techniques as a BMI except the interpretation of the data collected is varied. Information gathered using the percentile ranking takes into consideration the childs age and sex, recognising that the amount of body fat regularly changes with age and sex. The BMI-for-age highlights the values among children of the same sex and age and categorises overweight adolescents as being between the 80th percentile and less than the 95th percentile. Obese children are classified as being equal to or greater than the 95th percentile.

Although calculating an individuals BMI is the most recommended indicator it doesn't distinguish the risk of disease. Regular monitoring of fat distribution, genetics and fitness levels should be maintained to assess the likelihood of disease. Alternative ways in which an individual can have their weight assessed, other than a BMI test, includes measuring the circumference of their waist or using the skin fold test.

This is a list of the states of India ranked in order of percentage of people who are overweight or obese, based on data from the 2007 National Family Health Survey.

In the United States, the prevalence of obese or overweight adult dogs is 23–53%, of which about 5% are obese; the incidence in adult cats is 55%, of which about 8% are obese.

In Australia, obesity is the most common nutritional disease of pets; the prevalence of obesity in dogs in Australia is approximately 40%.

Although genetic deficiencies are currently considered rare, variations in these genes may predispose to common obesity. Many candidate genes are highly expressed in the central nervous system.

Several additional loci have been identified. Also, several quantitative trait loci for BMI have been identified.

Confirmed and hypothesized associations include:

Some studies have focused upon inheritance patterns without focusing upon specific genes. One study found that 80% of the offspring of two obese parents were obese, in contrast to less than 10% of the offspring of two parents who were of normal weight.

The thrifty gene hypothesis postulates that due to dietary scarcity during human evolution people are prone to obesity. Their ability to take advantage of rare periods of abundance by storing energy as fat would be advantageous during times of varying food availability, and individuals with greater adipose reserves would more likely survive famine. This tendency to store fat, however, would be maladaptive in societies with stable food supplies. This is the presumed reason that Pima Indians, who evolved in a desert ecosystem, developed some of the highest rates of obesity when exposed to a Western lifestyle.

Numerous studies of laboratory rodents provide strong evidence that genetics plays an important role in obesity.

The risk of obesity is determined by not only specific genotypes but also gene-gene interactions. However, there are still challenges associated with detecting gene-gene interactions for obesity.

Pregnant women who ate more sweets, such as candy and processed juices, in early pregnancy were at higher risk of gaining excessive weight. A healthy, well-balanced diet during pregnancy can also help to minimize some pregnancy symptoms such as nausea and constipation.

Several studies have shown that obese men tend to have a lower sperm count, fewer rapidly mobile sperm and fewer progressively motile sperm compared to normal-weight men.

Obesity in Germany has created a cholesterol problem. High cholesterol is known to cause premature death, angina, heart disease and strokes.

There has been an increase of children with Type 1 diabetes between 1996 and 2011. Diabetics are at higher risk for complications such as heart attack and stroke. In Germany, 600,000 people suffered from diabetes near the end of World War II compared to eight million now.

Obesity can increased risk for secondary diseases such as diabetes, cardiovascular disease, certain cancers and Alzheimer's. Children who get diabetes can expect to lose 10 to 15 years off of their lives. Diabetes also affect the eyes, kidneys and nerves in the legs.

Obesity is a "very strong promoter of cancer." Obesity causes an increased risk for colon cancer and breast cancer.

Although some genetic links to obesity have been made, relatively little is known about how genes or loci might influence dynamic measures of weight change over time.

Several studies have shown that obese men tend to have a lower sperm count, fewer rapidly mobile sperm and fewer progressively motile sperm compared to normal-weight men. Researchers in France have said that poor children were up to three times more likely to be obese compared with wealthier children.

In French society, the main economic subgroup that is affected by obesity is the lower class so they perceive obesity as a problem related to social inequality.

Researchers from the NIH's National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) conducted a study and found that early-onset paternal obesity is connected with an increased risk of liver disease in their kin. Researchers found that obese fathers had an elevated level of serum alanine aminotransferase (ALT), a liver enzyme, compared to fathers who were not obese. They did a secondary analysis that excluded obese offspring. Children who were a normal weight but had obese fathers still had elevated ALT levels, which indicated that a child's ALT levels are not dependent upon the child's own BMI.

A clothing-related study revealed that many clothing companies plan to adjust their sizing partly due to Germany's obesity epidemic.

There has been an increase in obesity-related medical problems, including type II diabetes, hypertension, cardiovascular disease, and disability. In particular, diabetes has become the seventh leading cause of death in the United States, with the U.S. Department of Health and Human Services estimating in 2008 that fifty-seven million adults aged twenty and older were pre-diabetic, 23.6 million diabetic, with 90–95% of the latter being type 2-diabetic.

Obesity has also been shown to increase the prevalence of complications during pregnancy and childbirth. Babies born to obese women are almost three times as likely to die within one month of birth and almost twice as likely to be stillborn than babies born to women of normal weight.

Obesity has been cited as a contributing factor to approximately 100,000–400,000 deaths in the United States per year (including increased morbidity in car accidents) and has increased health care use and expenditures, costing society an estimated $117 billion in direct (preventive, diagnostic, and treatment services related to weight) and indirect (absenteeism, loss of future earnings due to premature death) costs. This exceeds health-care costs associated with smoking or problem drinking and, by one estimate, accounts for 6% to 12% of national health care expenditures in the United States (although another estimate states the figure is between 5% and 10%).

The Medicare and Medicaid programs bear about half of this cost. Annual hospital costs for treating obesity-related diseases in children rose threefold, from US$35 million to US$127 million, in the period from 1979 to 1999, and the inpatient and ambulatory healthcare costs increased drastically by US$395 per person per year.

These trends in healthcare costs associated with pediatric obesity and its comorbidities are staggering, urging the Surgeon General to predict that preventable morbidity and mortality associated with obesity may surpass those associated with cigarette smoking. Furthermore, the probability of childhood obesity persisting into adulthood is estimated to increase from approximately twenty percent at four years of age to approximately eighty percent by adolescence, and it is likely that these obesity comorbidities will persist into adulthood.

Weight management has two steps: weight loss and weight maintenance. In the weight loss phase, energy intake from food must be less than the energy expended each day. Achieving weight loss in cats and dogs is challenging, and failure to lose weight is common.

Medical treatments have been developed to assist dogs in losing weight. Dirlotapide (brand name Slentrol) and mitratapide (brand name Yarvitan) were authorized for use in the EU by the European Medicines Agency for helping weight loss in dogs, by reducing appetite and food intake, but both of these drugs have been withdrawn from the market in the EU. The US Food and Drug Administration approved dirlotapide in 2007. Up to 20% of dogs treated with either dirlotapide or mitratapide experience vomiting and diarrhea; less commonly, anorexia may occur. When these drugs are stopped, the dog's appetite returns to previous levels. If other weight-loss strategies are not employed, the dog will again gain weight.

The French, along with the Italians and the Swiss, were previously considered to be among the slimmest people in Europe on average.

World Health Organisation (WHO) data published in 2014 showed however that adult obesity rates in France were significantly ahead of the Netherlands at 19.8%, Germany at 20.1% and Italy at 21.0%.

In 2010 38.5% of men and 26% of women in France were considered overweight while 60% of men and 43% of women in Germany were considered overweight. Estimates show that 16% of French five-to-11-year-olds are obese. Obesity in that age group is set to increase to more than 20% by 2010.

Obesity in children is growing at a faster rate than obesity in adults. Obesity in children is growing at a rate of 17% while obesity in adults is growing at a rate of 6%. Recent studies show a slowdown in the growth of obesity in France especially for children.

1 in 4 children are overweight (25%) and 2 in 3 adults are overweight (63%)

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.