Just 4 percent of agricultural subsidies go to fruits and vegetables. No wonder that the healthiest foods can cost up to eight times more, calorie for calorie, than the unhealthiest—or that the gap gets wider every year.

It’s the same with exercise. The cardiovascular risks of sedentary lifestyles, suburban sprawl and long commutes are well-documented. But rather than help mitigate these risks—and their disproportionate impact on the poor—our institutions have exacerbated them. Only 13 percent of American children walk or bike to school; once they arrive, less than a third of them will take part in a daily gym class. Among adults, the number of workers commuting more than 90 minutes each way grew by more than 15 percent from 2005 to 2016, a predictable outgrowth of America’s underinvestment in public transportation and over-investment in freeways, parking and strip malls. For 40 years, as politicians have told us to eat more vegetables and take the stairs instead of the elevator, they have presided over a country where daily exercise has become a luxury and eating well has become extortionate.


The good news is that the best ideas for reversing these trends have already been tested. Many “failed” obesity interventions are, in fact, successful eat-healthier-and-exercise-more interventions. A review of 44 international studies found that school-based activity programs didn’t affect kids’ weight, but improved their athletic ability, tripled the amount of time they spent exercising and reduced their daily TV consumption by up to an hour. Another survey showed that two years of getting kids to exercise and eat better didn’t noticeably affect their size but did improve their math scores—an effect that was greater for black kids than white kids.

You see this in so much of the research: The most effective health interventions aren't actually health interventions—they are policies that ease the hardship of poverty and free up time for movement and play and parenting. Developing countries with higher wages for women have lower obesity rates, and lives are transformed when healthy food is made cheaper. A pilot program in Massachusetts that gave food stamp recipients an extra 30 cents for every $1 they spent on healthy food increased fruit and vegetable consumption by 26 percent. Policies like this are unlikely to affect our weight. They are almost certain, however, to significantly improve our health.