The world’s most expensive health care system has the sickest citizens among wealthy countries, and they are getting sicker every day.

Tens of millions of these chronically ill Americans will gather to feast on Thanksgiving Day. About 40 percent of the adults sitting around the table will be clinically obese, as will be 18 percent of the children, according to the National Health and Nutrition Examination Survey.

The proportion of Americans over the age of 20 with diabetes has risen from 10 percent in 2000 to almost 15 percent in 2016, the last year that the Centers for Disease Control has analyzed. More than 30 percent of Americans have hypertension.

As a result, the life expectancy for the average American at birth has dropped, the CDC reports. Heart disease, respiratory ailments, stroke and diabetes were among the top causes of death. Personal behavior plays a significant role.

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Political candidates are debating how to fix the nation’s health care system, offering solutions ranging from socialized medicine to transparent pricing. But few have the guts to call out the American people themselves for being fat, dumb and dying.

Americans, on average, have dreadful eating and exercise habits. Most Americans consume too much sugar, salt and fat, and half overeat cheap, fast food high in calories and low in nutrition. And three out of four do not eat enough fruit and vegetables, according to the National Institutes of Health.

When those adults have children, they create a generational crisis. Poor eating habits hamper healthy development and create bad habits that last a lifetime. And no, most American children are not naturally husky. According to pediatric researchers, most obese children simply eat too much.

The more home-cooked meals a child eats, the healthier they tend to be. But U.S. children consume more calories from fast food than they do from school food and home-cooked meals are infrequent, according to a University of North Carolina study.

America’s obesity epidemic is one of the biggest challenges facing the U.S. economy. Rising childhood obesity will bring a tsunami of health problems when these kids reach adulthood and run up huge medical bills.

Economists would suggest that higher care costs should incentivize people to maintain their health. But rising obesity and preventable disease rates have coincided with skyrocketing health care costs for decades, and Americans keep ruining their health.

The U.S. spends roughly three times as much per person on health care as other wealthy countries. And despite our amazing hospitals and research institutions, Americans are underserved and less healthy, the latest Organization of Economic Cooperation and Development research reveals.

The U.S. has fewer people with health care coverage, fewer families with access to primary care doctors and fewer doctors per capita. And despite our fast food brands spanning the globe, Americans have shorter lives, more disease and more obesity.

Biologists understand human behavior better than economists. They know every creature seeks the maximum number of calories for the least amount of effort. Since calories in America are easily obtained with little physical effort, nature is out of balance.

Medicare for All is not going to override mammalian instincts. Forcing hospitals and doctors to publish their secret price lists will not encourage healthier lifestyles. Capping insurance company profits will not make lean protein and green vegetables cheaper than fried, sugar-coated carbohydrates.

Research shows that piling costs onto individuals does not change bad behavior, and in large-scale trials, neither does financial incentives for healthy behavior. Biologists know the only solution is to limit an animal’s access to calories. Here is where economists can help.

History frowns on government-induced famines, but we can use economic carrots and sticks to encourage healthier choices and complicate access to bad calories. It may be the only way to save the nation from a health-cost-induced bankruptcy.

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Taxing sugary, harmful products to make them more expensive is unpopular but necessary. The revenues should be used to reduce the supply chain costs of delivering fresh food to everyone.

As a society, we must also vilify the supersize culture. Food producers promoted this marketing trick to sell more food and boost profit margins. But portion control is a critical healthy habit.

Finally, Americans need to learn that dieting does not work. Getting healthy means changing everything forever, both diet and exercise. Giving up potato chips for a month does nothing.

Americans are entitled to a range of food and behavior choices. Still, while no one should take that away, society also has a responsibility not to encourage behaviors because we are the ones who will pay the bill in the long run.

Tomlinson writes commentary about business, economics and policy.

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chris.tomlinson@chron.com