The average adult body weight in the US (2010) is 88.7 kg for men, and 75.4 kg for women; and the obesity rates are also high. The standard definition of obesity in the United States is a BMI^* of 30 or higher. By this definition 36% of the adult population is obese, by far the highest level among OECD member countries. A BMI of 25 and over is considered to be overweight. The percentage of overweight US adults is 68%, nearly five times the rate in Japan (14%). Furthermore, the big problem is that there is no stop to this trend of increasing obesity. The average weight of both males and females has increased by about 12 kg compared to 50 years ago, and the rate of obesity has increased by a factor of 2.7 from 13.4% in the early 1960s.

So why have Americans become so fat? According to the experts, there is no single cause; instead, it is the result of several, seemingly harmless, changes. It has become easy to obtain high-calorie foods at a low cost as a result of an increase in food supplies and technological innovations to achieve high productivity in food production, which were developed to overcome problems of malnutrition that existed in the past. Ironically, obesity rates tend to be higher in low-income groups. There are also those who raise concerns about the increase in amounts of antibiotics, etc. that are being administered to livestock. It has also been pointed out that with the development and structural changes of the US economy people work longer hours, and more women are working outside the home, leading to an increase in the number of people who eat high-calorie junk food for their meals. On top of this, people aren't getting enough exercise. With urbanization and a decline in physical labor, it has been estimated that Americans today are getting nearly 30% less exercise compared to half a century ago.

Acronym for Body Mass Index. Calculated from height and weight.

The increase in obesity in the United States imposes new burdens on the economy and society, such as increased health care costs. According to the US Centers for Disease Control and Prevention (“CDC”), medical costs due to obesity in the US as a whole are nearly USD 150 billion annually. There are even estimates that the total cost of obesity, including the indirect effects, is equivalent to 1% of the GDP. The US must apply the brakes to increasing obesity; the fight against obesity can no longer wait.

However, there are various and wide-ranging factors that cause the increasing obesity. No decisive countermeasure has been found, so the government and private sector can only keep trying different measures and approaches that seem to offer some hope of being effective. Nevertheless, there have been some results seen in controlling obesity in children. In a 20 year period up through 2010 the rate of obesity in children between the ages of six and eleven tripled, and diabetes became a disease that was not uncommon in children. Everyone agreed that changing this situation was the top priority. In 2010, the First Lady, Michelle Obama, started a prototypical campaign called “Let's Move!”, designed to eliminate obesity in children. Fast food restaurants also began reviewing their children's menus, and many day care centers and schools started working to improve standards of nutrition and exercise. The success of these efforts is shown by the recently-announced obesity rates among children between the ages of two and five years in 2012, dropping from 14% to 8%, nearly half the level of 2004.

That said, during the same period, the rate of obesity among everyone between the ages of two and 19 years remained 17%, and the obesity rate among women over the age of 60 actually rose from 32% to 38%. These illustrate that measures to fight obesity in the US are still a work in progress. It has finally become more common for fast food restaurants to display the calories contained in the items they serve, but the set menus with more than 1,000 kilocalories are still being offered. Nevertheless, it is clear that the fight against obesity is gradually gaining momentum. It will probably take some time, but the American people as a whole, at all income levels, should be able to gradually become conscious of calories and how to prevent obesity.