How government subsidies, taxes and restaurants affect our weight

Over the holiday weekend, many Americans enjoyed the tastes of freedom: hot dogs and hamburgers fresh off the grill; corn dripping with melted butter; potatoes flash-fried in oil, smothered in mayonnaise, covered with salt. At parades, parks and backyard barbecues everywhere, the high-fructose corn syrup flowed freely.

Alas, as we are so often reminded, freedom isn’t free. And, as a bumper crop of research reminded us on Tuesday, neither are our dietary choices.

American diets are shaped by federal agricultural subsidies that assure cheap and easy access to the highest-calorie foods. Restaurants add salt and saturated fats to lure us away from our kitchens at dinnertime. Tax initiatives that could reduce consumption of sugar-sweetened drinks are routinely beaten back by beverage producers.

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Factors like these have combined with our busy lifestyles, our genes and our natural attraction to calorie-rich foods to fuel a stunning rise in the nation’s obesity rate. Experts say 35% of American adults — 78.6 million people — are obese. So are 17% of American kids, or 12.7 million children. All these extra pounds add billions of dollars to the nation’s healthcare bill each year.

Here, like a post-holiday hangover, is a roundup of study findings issued Tuesday:

Do government subsidies make us fat?

Federal agricultural dollars subsidize the production of foods that have a disproportionate role in making Americans fat, according to research published in JAMA Internal Medicine.

Federal subsidies of corn, soybean, wheat, rice and sorghum have given Americans the makings for high-calorie juices and soft drinks, highly processed baked goods and processed foods, and high-fat meat and dairy products. More than half the calories consumed by American adults come from crops heavily subsidized by the federal government. For the young, the poor, the less educated and less food-secure, reliance on these foods is far higher.

Using a one-day dietary recall survey, researchers compared adults who ate the most federally subsidized foods with those whose consumption was lowest. The biggest consumers of subsidized foods had a 37% higher risk of being obese, a 41% higher risk of having belly fat and a 14% higher risk of high cholesterol.

The findings support calls “to realign agricultural policies to nutritional needs in the modern era of increasing cardiometabolic diseases,” the authors wrote. They recommend shifting subsidies toward greater production of fruits and vegetables.

Could junk food taxes fight obesity?

In early 2014, Mexico passed an 8% tax on junk foods — including salty snacks, chips, cakes and frozen desserts — and a roughly 10% tax on sugar-sweetened soda. Within one year, the effect was readily detectable: People purchased about 5% less of these items, by volume, than they would have otherwise, said a study published in the journal PLOS Medicine.

That translates into a monthly reduction of between 75 and 110 calories per person, the study authors wrote. But they added that Mexicans are probably reducing their calories far more steeply, because the taxed foods they tracked represent a small fraction of all those affected by the new tax.

The lower one’s income, the greater the effect of the tax, the study found. Among low-income Mexicans, the new taxes drove down purchases of high-fat and high-calorie food and beverages by more than 10%. The researchers saw no changes in people’s purchases of foods unaffected by the taxes, suggesting it was the tax — not shifting tastes — that prompted the falloff in consumption.

Mexico has an obesity rate even higher than that in the United States.

What if we ate at home instead?

People who said they ate dinner at home five to seven times a week had a 15% lower risk of Type 2 diabetes than those who consumed two or fewer dinners at home per week, according to another study in PLOS Medicine.

In research that tapped into two large studies of U.S. health professionals, participants who ate out gained more weight than those who ate more meals prepared at home. That weight gain was considered a key driver of diabetes.

A smaller, but still statistically significant, reduction was apparent for those who reported consuming homemade lunches more often.

The new research is in line with a welter of studies that have linked meals prepared and eaten away from home — especially at fast-food restaurants — with higher weight and poorer health.

melissa.healy@latimes.com

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