Overeating, lack of health insurance access and comparatively high poverty are among the many reasons why Americans are less healthy and die younger than people in other wealthy countries, a report requested by the U.S. government showed on Wednesday.

The United States spends more per person on healthcare than any other nation but lags on many important health measures amid higher rates of obesity and heart disease and worse infant mortality rates than other rich countries.

The 404-page report by the National Research Council and Institute of Medicine, which provide advice to U.S. policymakers, compared the health of Americans to that of people in 16 other rich countries. They included Canada, Japan, Australia and 13 western European countries including Britain, France, Italy, Switzerland and Germany.

"Americans are dying and suffering at rates that we know are unnecessary, because people in other high-income countries are living longer lives and enjoying better health. What concerns our panel is why, for decades, we have been slipping behind," said Steven Woolf, a medical professor at Virginia Commonwealth University who led the panel that produced the report.

Americans overall fared the worst among the countries in the report when it came to nine areas: infant mortality; injury and homicide rates; teen pregnancy and sexually transmitted diseases; HIV infection and AIDS; drug abuse; obesity and diabetes; heart disease; lung disease; and disabilities.

"No single factor can fully explain the U.S. health disadvantage," the researchers said.

The report, sought by the U.S. government's National Institutes of Health, underscored what health experts have long known: Americans on average die younger than people in other rich countries and are in poorer health for much of their lives.

Two-thirds of Americans are considered overweight or obese. The report also noted that Americans on average consume more calories than people in most similar countries and have lower physical activity levels.

The United States also has a higher infant mortality rate than the other countries, with 32.7 deaths per 100,000, the report showed. Most similar countries have infant mortality rates between 15 and 25 deaths per 100,000.

"The U.S. health disadvantage has multiple causes and involves some combination of inadequate healthcare, unhealthy behaviors, adverse economic and social conditions, and environmental factors, as well as public policies and social values that shape those conditions," it said.

President Barack Obama in 2010 signed a law vigorously opposed by Republicans in Congress intended to improve access to medical insurance and rein in healthcare spending.

The U.S. healthcare system is a patchwork of private insurance often provided through an employer as well as public programs aimed at the elderly, disabled and poor. Tens of millions of Americans are left with no insurance to help pay for care.

Some major parts of the U.S. law have yet to take effect and critics challenge many aspects of it.

People in other rich nations generally get medical care through national healthcare systems.

LIFE EXPECTANCY

Americans on average are living longer than in the past, but the lifespan gains lag those of other nations, the report found.

U.S. men ranked last when it comes to longevity - about 75.6 years compared to 79 years for men in Switzerland, the top-ranked country. U.S. women ranked next to last, living about 80.8 years compared to 86 years for women in No. 1-ranked Japan.

"This disadvantage has been getting worse for three decades, especially among women," researchers said.

Americans fared better in some areas with fewer deaths from cancer and better control of cholesterol and blood pressure.

Understanding the reason for poorer outcomes despite the roughly $2.6 trillion, and rising, that the United States spends annually on healthcare is a major issue as the nation struggles to revive its economy.

"Shorter lives and poorer health in the United States will ultimately harm the nation's economy as healthcare costs rise and the workforce remains less healthy than that of other high-income countries," the researchers wrote.

While part of the problem is likely linked to the increased gap between wealthy and low-income Americans and higher levels of poverty overall, the report said that does not fully explain the U.S. disadvantage. The report noted that even educated, upper income Americans with health insurance "are in worse health" than similar people in the other countries.

The researchers said the United States should look at policies that work in countries "with superior health" to seek answers. Without action, they said, "the health of Americans will probably continue to fall behind."