Calories consumed daily by the typical American adult, which peaked around 2003, are in the midst of their first sustained decline since federal statistics began to track the subject, more than 40 years ago. The number of calories that the average American child takes in daily has fallen even more — by at least 9 percent.
— including higher- and lower-income families, and blacks and whites — though they vary somewhat by group.
In the most striking shift, the amount of full-calorie soda drunk by the average American has dropped 25 percent since the late 1990s.
The reversal appears to stem from people's growing realization that they were harming their health by eating and drinking too much. The awareness began to build in the late 1990s, thanks to a burst of scientific research about the costs of obesity, and to public health campaigns in recent years.
The encouraging data does not mean an end to the obesity epidemic: More than a third of American adults are still considered obese, putting them at increased risk of
. Americans are still eating far too few fruits and vegetables and far too much junk food, even if they are eating somewhat less of it, experts say.
But the changes in eating habits suggest that what once seemed an inexorable decline in health may finally be changing course. Since the mid-1970s, when American eating habits began to rapidly change, calorie consumption had been on a near-steady incline.
"I think people are hearing the message, and diet is slowly improving," said Dr. Dariush Mozaffarian, the dean of the Friedman School of Nutrition Science and Policy at Tufts University.
Barry Popkin, a University of North Carolina professor who has
studied food dataextensively, described the development as a "turning point.
There is no perfect way to measure American calorie consumption. But
three large sources of data about diet all point in the same direction. Detailed daily food diaries
tracked by government researchers, data from food bar codes and estimates of food production all show reductions in the calories consumed by the average American since the early 2000s. Those signals, along with the flattening of the national obesity rate, have convinced many public health researchers that the changes are meaningful.
The eating changes have been the most substantial in households with children. Becky Lopes-Filho's 4-year-old son, Sebastian, has always been at the top of the
growth chart for weight. Ms. Lopes-Filho, 35, is the operations manager of a pizzeria in Cambridge, Mass., and her son, like her, loves food. As he has gotten older, she has grown more concerned about his cravings for sweets. Instead of a cookie every day now, she said, she has been trying to limit him to one a week. "If he was given access, he would just go nuts," she said. "He, I think, would tend to be a super obese kid."
There is no single moment when American attitudes toward eating changed, but researchers point to a 1999 study as a breakthrough. That year, researchers from the Centers for Disease Control and Prevention published a paper in The Journal of the American Medical Association that turned into something of a blockbuster.
The paper included
bright blue maps illustrating worsening obesity rates in the 1980s and 1990s in all 50 states. Researchers knew the obesity rate was rising, but Dr. Ali Mokdad, the paper's lead author, said that when he presented the maps at conferences, even the experts were gasping. A year later, he published
another paper, with a similar set of maps, showing a related explosion in diabetes diagnoses. "People became more aware of it in a very visual and impactful way," said Hank Cardello, a former food industry executive who is now a senior fellow at the Hudson Institute, a conservative policy center. "That created a lot of attention and concern."
Shortly afterward, the surgeon general, Dr. David Satcher, issued a report — "
Call to Action to Prevent and Decrease Overweight and Obesity" — modeled on the famous 1964 surgeon general's report on tobacco. The 2001 report summarized the increasing evidence that obesity was a risk factor for several chronic diseases, and said controlling children's weight should be a priority, to prevent the onset of obesity-related illnesses.
The Obama administration has
increased pressure. The Affordable Care Act, passed in 2010, required chain restaurants to
publish the calorie content of their meals. The federal government has also changed requirements, making school lunches healthier, although the effort has created
some backlash.
Several cities have gone further. Philadelphia
subsidizes produce purchases for the poor. New York limits the kind of food available in
day care centers. Berkeley, Calif., last year became the first city in the United States to
tax sugar-sweetened beverages. The evidence for the effectiveness of these interventions is mixed, but their popularity reflects public health officials' emphasis on diet and obesity.
Still, the timeline of the calorie declines suggests that people started eating a little less before policy makers got involved. That follows the
pattern for tobacco use, which peaked right around the time of the 1964 surgeon general's report. The policy changes that many credit with the country's sharp reductions in smoking — advertising bans, warning labels, taxes and restrictions on smoking in public — came later, accelerating change after attitudes had already begun to shift.
The anti-obesity public health campaigns have focused on one subject more than any other: beverages.
Anti-soda messages hit their target. Americans, on average, purchased about 40 gallons of full-calorie soda a year in 1998, according to sales data from the industry trade publication Beverage Digest analyzed by the Center for Science in the Public Interest. That fell to 30 gallons in 2014, about the level that Americans bought in 1980, before the obesity rates took off.
"I think the attitude more and more in this country is that it's not a good idea to consume a lot of soda," said Dr. Satcher, now a professor at the Morehouse School of Medicine in Atlanta.
Beverage companies have reacted by marketing diet drinks and investing heavily in new products, including iced teas
and flavored water. "A lot of the changes we are seeing are consumer-driven," said John Sicher, Beverage Digest's publisher.
Outside of beverages, there are few clear trends. Experts who have examined the data say the reductions do not mean that Americans are flocking to farmer's markets and abandoning fast food. Consumption of fruits and vegetables remains low; consumption of desserts remains high. Instead, people appear to be eating a little less of everything. Although consumption in nearly every category has been "cut some," said Mr. Popkin, "the food part of our diet is horrendous and remains horrendous."
The calorie reductions are seen across nearly every demographic group, but not equally. White families have reduced their calorie consumption more than black and Hispanic families. Most starkly, families with children have cut back more than households with adults living alone, further evidence, experts say, that the public health emphasis on childhood obesity is driving the changes.
Ms. Lopes-Filho said she's seen how her concern about her son's diet has subtly changed her own eating habits. "I think I'm still sneaking stuff behind his back, but I have tried to change," she said. "I haven't been drinking soda or doing a lot of sugary drinks in a while, but all because of him — because I know that if I have it, he's going to want it. And there's really no fair way to say, 'No, this is Mommy's drink.' "
Perhaps the biggest caveat to the trend is that it does not appear to extend to the very heaviest Americans. Among the most overweight people,
weight and
waist circumference have all continued rising in recent years.
The recent calorie reductions appear to be good news, but they, alone, will not be enough to reverse the obesity epidemic. A paper by Kevin Hall, a researcher at the National Institutes of Health, estimated that for Americans to return to the body weights of 1978 by 2020, an average adult would need to reduce calorie consumption
by 220 calories a day. The recent reductions represent just a fraction of that change.
"This was like a freight train going downhill without brakes," Kelly Brownell, dean of the Sanford School of Public Policy at Duke University, said. "Anything slowing it down is good."
More information about the data sources we examined, and their various strengths and weaknesses,
can be found here.
