A new study says that obesity cost the United States $75bn (£40bn) last year.
By Jannat Jalil
BBC correspondent in Washington
The study by the Centre for Disease Control and Prevention found that more than half that amount - nearly $40bn
(£21bn) - came out of public taxes.
The researchers say these figures show that urgent action needs to be taken to reduce the number of dangerously overweight people.
The US recently blocked international efforts, led by the World Health Organisation, to combat obesity.
The researchers who carried out the study say they are alarmed by the growing costs of obesity - both to America's economy and to the health of its people.
Obesity is now a global problem
A third of Americans are overweight, and another third are obese. This means that they are far more likely to suffer heart problems, diabetes and a host of other chronic diseases.
As the study shows, Americans' expanding waistlines are also putting a huge strain on America's health care system.
This problem is not unique to the United States. Obesity is increasing rapidly around the world.
But a global plan to reduce it - put forward by the World Health Organisation (WHO) earlier this week - was delayed because of objections from the United States.
The WHO plan calls for governments to force food companies to reduce the amount of sugar and fat they put in their products.
But the US opposes this. It says it does not accept that heavy marketing of high-calorie processed foods is causing obesity.
But critics say the United States is acting in the interests of its powerful food industry, rather than its overweight population.