Posted
Feb 2010
Are Restaurants Really Supersizing America?
Restricting restaurant meals may not trim Americans’ expanding waistlines
Based on the research of Michael Anderson And David A. Matsa
There is an inherent tension in the field of public health: How do you effect the greatest good for the greatest number of people without denying them personal freedom? It might seem reasonable to impose a quarantine during an outbreak of a highly infectious disease with a terrifying fatality rate, but how should we regulate factors that contribute to slow killers such as diabetes, hypertension, and obesity?
Since 1980, the rate of obesity has been increasing so steadily that nearly half of all Americans are expected to be obese by 2020. As our waistlines grow, public health officials are looking for ways to shrink our appetites. According to obesity research, the average American’s weight is not the only thing increasing. The number of restaurants in the United States is at a record high. People eat restaurant food more often than ever before, and people who report high consumption of restaurant food—particularly fast food—are heavier than those who eat food cooked at home.
But does eating in restaurants cause obesity? David Matsa (Assistant Professor of Finance at the Kellogg School of Management) and Michael Anderson (Assistant Professor of Agricultural and Resource Economics at the University of California, Berkeley) conducted a comprehensive study of the question. “There are arguments that could lead you to believe there would be a causal relationship, so we wanted to understand if this was true,” Matsa says.
Our work should not be used to trivialize problems related to obesity, but to promote policies that are more likely to succeed in reducing them.
Many policy makers assume that eating out does contribute to obesity. Los Angeles will not permit new fast-food restaurants to open in South L.A., an area beset by obesity and poverty. Following in New York State’s footsteps, California and the cities of Philadelphia, Portland, and Seattle are moving to require chain restaurants to print nutrition information, including calorie counts, on menus. Washington State is considering a tax on fat-laden foods such as burgers and fries.
Matsa and Anderson addressed the problem by analyzing real-world data, including surveys on calorie consumption and maps of restaurant availability and accessibility. Matsa notes that theirs is the only study of restaurant proximity and obesity separates supply from demand in addressing a fundamental question: Does the number of nearby restaurants cause people to eat more, or are restaurants more numerous because people are eating more?
Roadside Diners
Matsa and Anderson wanted to know if people who live closer to restaurants weigh more than those who live farther away. A meal’s tab is not the only cost of eating out: The farther a consumer lives from a restaurant, the higher the cost in fuel, time, and effort. If cost was a deciding factor, those who lived closer to dining establishments would be more likely to eat out and—if restaurants were indeed at fault—would be more likely to be obese.
Matsa and Anderson looked at data from the Behavioral Risk Factors Surveillance System. Each year, state health departments phone a sample of residents and ask them about their habits and health, including their height and weight. These measures are used to calculate respondents’ body mass indexes, an estimate of body fat. A body mass index of 25 or higher indicates that a person is overweight; 30 or higher is considered obese.
Eleven states provided data that included the first six digits of the respondents’ phone numbers. Because landline numbers are tied to geographic locations, Matsa and Anderson could determine respondents’ proximity to highways. In the rural United States, restaurants typically are clustered around limited-access highway exits.
Matsa and Anderson focused on rural areas—those at least 30 miles from urban areas with fewer than 80 people per square mile—because nearly everyone in more densely populated urban settings has easy access to restaurants. The highway model also ensures that the abundance of nearby restaurants is not a factor of their use by local residents. Because restaurants are often located near highways to serve customers passing through, their density in those areas is higher than what the local population would support on its own. Had they not used the highway approach, Matsa and Anderson might have inadvertently sampled a population with a fondness for restaurant food that increased both their waistlines and the number of local restaurants.
“There is a lot of work relating body mass to how often people eat out, to the growth in restaurant density, and even to how far restaurants are located from schools. But none of those studies tries to account for consumer preferences or examines variation in the supply of restaurants, which is what we were trying to accomplish with the highway method,” Matsa says.
Using highways as a guide revealed some surprising results. Matsa and Anderson found that respondents’ proximity to a highway, and therefore to restaurants, did not correlate to increased body mass. No matter how near to or far from a highway respondents lived, body masses were nearly the same (see Figure 1).
Figure 1: Distribution of Body Mass Index in Towns Adjacent and Nonadjacent to Interstate Highways
Still, Matsa and Anderson needed a finer level of detail to eliminate the possibility that all the respondents were eating at restaurants—or not—regardless of how far they lived from a highway, so they surveyed restaurant customers in an area similar to those covered by the health department phone surveys. They canvassed 23 fast-food restaurants along Interstate 5 in rural California, asking more than 2,000 customers to identify their zip codes and the towns where they lived. They learned that people who lived within five miles of a restaurant ate out about twice as often as those who lived five to ten miles away, confirming their premise that restaurant visits decreased as the dollar and time costs of traveling for food increased.
The Cost of Consuming
Matsa and Anderson recognized that per-meal costs also influence how much people eat when they visit restaurants. In general, outsized portions are not typically priced significantly higher than more reasonable servings, meaning that cost does not dissuade diners from eating additional calories. In addition, diners are more likely to clean their plates when eating out because their money has already been already spent.
A homemade meal, however, does not prompt the same “I own it, I’m eating it all” response. Those who eat food cooked at home consume less: There is not much to gain by feeding an already-full belly. In economic terms, this is the principle of diminishing marginal utility—the notion that the more you have of something, the less you want still more. If you have just eaten a half-pound of homemade spaghetti, you have probably sated your appetite and are not interested in another serving.
Matsa and Anderson also investigated the role of supply and demand—whether the increase in the number of restaurant meals caused people to consume more calories, or people’s increased caloric demand drove up the number of restaurant meals. They devised a theoretical model to represent consumers’ dining choices, breaking down the factors that influence an eater’s decisions into a simple cost-per-calorie ratio. When their model was altered so both home and restaurant meals were priced equally, some people still ate more than others, reflecting individual preferences. Their results were confirmed by food diaries collected by the U.S. Department of Agriculture, in which people reported what they ate on two nonconsecutive days.
“There is a selection issue,” Matsa explains. “People who eat at restaurants more often might be doing so because they’re hungry for larger meals.” Thus, big eaters eat more no matter where they are, whether at home or dining out.
Although people do eat more when they eat in restaurants, Matsa and Anderson found that diners compensate for those typically highly caloric meals by curtailing what they eat at home during the rest of the day. Again, marginal utility suggests that eating beyond satiety delivers diminishing returns, a result that was empirically supported by the food diaries, according to Matsa. Restaurant meals, while larger, may not have a net effect on calories consumed or body mass. When it comes to obesity, restaurants may not be at fault.
Regulating Repast
While living closer to restaurants increases the frequency of dining out, “restaurants really don’t seem to have a causal effect on body mass,” Matsa says. Without conclusive proof, Matsa and Anderson do not think regulating restaurants is warranted. They calculate that a “sin tax” on restaurant food—like those levied on alcohol and cigarettes and recently proposed for sugary beverages—as high as 50 percent would increase the cost of the average restaurant meal by $3.97 but reduce body mass by only 0.004 points. People who eat too many calories will continue to find ways to do so, even when economic pressures limit some of their choices.
“Our work should not be used to trivialize problems related to obesity,” Matsa remarks, “but to promote policies that are more likely to succeed in reducing them.”
15 Comments
Feb 5 2010
Very interesting research!
Feb 5 2010
Perhaps one reason why restaurants don’t have ” a causal effect on body mass” is that whether food is bought in restaurants (especially fast food) or grocery stores, the vast majority of food in America is processed food. A tomato or grain of rice is real food. Nearly everything in a grocery store is processed, including the packaged stuff that claims to be healthy. A chicken nugget isn’t simply cooked chicken breast, it actually contains over 30 ingredients in it. A more interesting study would be the effect of the increase in availability of processed food on obesity. Michael Pollan has done some excellent work on this, in “The Omnivore’s Dilemma” and even better “In Defense of Food”. “The Blue Zone” is another excellent book whose focus is on longevity, but also discusses how the increase in processed food vs. natural food has changed waistlines and health.
Feb 17 2010
I totally agree. It’s the processed food that is causing the problem. Besides, putting a “sin-tax” on restaurant food is bad for the economy. If eating out starts costing people that much more, they will end up staying at home and still eat the junk that causes them to be obese. Is the unemployment situation in the country doing that good that we’d like to discourage people from eating out so we can close down restaurants and jobs? These “sin taxes” should be put on the right things - such as sugary beverages/ pop drinks.
Feb 17 2010
As a family, we have discussions regarding this subject frequently. One of the challenges to eating healthy is the cost. Processed foods are always cheaper than their healthier alternatives. Restaurants fall into this same dilemma as they look to keep costs in control. As much as I hate to advocate Government intervention in our daily lives, we should look at added taxes being applied to processed foods and that money being funnelled into tax credits to farmers who grow untreated meats and vegitables.
Feb 17 2010
I agree with both the previous comments, and I would add that many countries in Europe do not have the rampant obesity problems we have in the US. When I talk to colleagues from those countries, they say that foods in the US are way too sweet and that their country does not allow high fructose corn syrup as a sweetener. This is just one example of the food industry being socially irresponsible to the American public. There are many other from nitrites in meat to genetically modified foods, and the public is generally unaware of what they are eating.
A “sin” tax actually could cause the food industry to rethink their motives, and work to the benefit of Americans.
Feb 17 2010
Typically these “sin taxes” become ingrained into our government’s resource model; whether or not they actually impact on the “sins” they were designed to reduce. The worse of all possible scenarios is that the tax does not “fix” the problem, and we increase to cost of living; keeping in mind when was the last time a tax like this is easily rescinded?. We should be very cautious for these seemingly “easy fixes” that do not positively correlate.
Feb 17 2010
Diabetes runs rampant in my own family: My grandfather and my son had/have type 1 diabetes. All of my aunts and uncles had type 2 diabetes, as do I.
I keep my son’s and my blood glucose tightly controlled by cooking at home every night. I have fabulous (nutritious) recipes that over time I have made even better. Fresh vegetables, fruits, lean protein, whole grains, etc. I use flaxseed, unprocessed wheat bran, and other wholesome grains.
My 15-year old son (and his older siblings who do not have diabetes) love my cooking! He is normal weight, and in tight control. My son will tell you that since the age of 4 when he was diagnosed with diabetes he has not been hungry, nor has he felt deprived. He loves food, but does not overindulge. Some of that is self-discipline, plus I never made him clean his plate. Mostly, he enjoys the recipes.
I wonder if I opened a bistro with the entire menu being diabetes-friendly (the same meals I cook at home, including desserts) would it catch on?
It’s more than being able to afford fresh foods. Not everyone has the desire or skill to cook well. A restaurant solves that problem.
Any thoughts?
Feb 17 2010
This would be a good idea - to tax or put fees on “junk” foods to subsidize good foods. my thought comes from one of Oprah’s show on low calories diets. They showed a guy who owns Dole company, he is an older gentleman and in terrific shape, he claims that he owes this to his fantastic diet of a lot of fresh fruit and vegetables. They showed his fridge and it was full of healthy stuff.
Now, I do not make alot of money but I do consider myself lower middle class and I can afford to buy things like free range proteins and some fresh produce, so i am wandering how many north american house holds cannot afford to buy real foods or are opting out to save some money??? Our neighbours are living on Hamburger helper and no name processed junk and I can see the how eating this will affect the BMI.
So, going back to my original thought and supporting another comment - what if we make it financially feesable for more people to buy things that are real and are made of basic food ingidients and not of food colouring #ABC123 and poly carbon benzonites. I think some of us still remember that pumpkin pies used to be made with 5 ingridients: flour, sugar, water, pumpkin and care and not 19 random combinations of elements on periodic table.
Feb 18 2010
The research and comments so far are all very interesting. I still wonder how restaurants take such a beating for people being overweight and video game makers get a total pass. Does a child work up such an appetite after playing video games for 2 hours the only thing that will fill him is McDonald’s? Yes, the offerings are huge. Yes, there is a high sugar content. Really though, is it really the fault of restaurants that kis don’t excercise like they used to in 50’, 60’s and 70’s? I say have kids play Wii fit and then let them have 12 ounces of soda to drink (and no Johnny, that wasn’t a sample).
Feb 26 2010
As a follow on piece of research what might be helpful is the tendency in America to “super size” portions - whether it is restaurants, fast food chains, or even grocery stores.
It may be worth examining other similar developed countries to see how they have avoided the obesity trap (e.g. Canada, U.K.)
A couple of comments have already alluded to the quality of food consumed (affordability being a key consideration) but portion sizes are an equal concern, particularly portion sizes of food that is increasingly of poorer quality (see the Food Inc, documentary).
The ability to produce food more cheaply to sell more, and simultaneously encouraging the population to consume more is likely to be a key culprit.
Sep 22 2010
did all the comments stop in february?
perhaps all the commenters should have to put in their BMI when they say something. i think mine is around 22. i weigh 140 and am 5’7” but shrinking because i’m getting old.
when i talk about not eating something (usually dessert), people tend to say “but joey, look at you, you’re skinny…shouldn’t be a problem.” as if i was born to be skinny.
i take my wife’s weight-watchers mantra. if you’re not hungry, don’t eat. if you’re full, stop eating. i prefer grazing to having meals. i’m surprised that nobody mentioned what i almost always do: take home leftovers from restaurants. unfortunately, this is not an option at buffets.
obviously, people are concerned about their “freedom” to over-consume. they’re not too concerned about the burden on the health system. indeed, i’ll bet research would show that many of them visit emergency rooms rather than doctors.
Feb 25 2011
As a Type I diabetic of almost 40 years, I agree with Aggie P’.‘s comments. It is just easier for most people to eat out and forget about common dietary guidelines. Fortunately, my wife cooks most every night; salads, protein, slow absorbing carbs, and occasional desert. How many families eat like that anymore? Very few, I think.
I mostly bring a sandwich to my office and eat it with a piece of fruit and then proceed to spend my ‘lunch hour’ walking for 30 minutes every day-yes, even after the blizzard.
I am not saying I don’t go out for dinner because I do. I tend to eat in moderation; a lot of salads an fish. I also very rarely visit a fast food restaurant; maybe every 6-9 months or so. Yes, I order a burger with a diet drink.
I am not suggesting that we have a tax on restaurants. A great first step would be for the government to control what food is provided in schools. In most, it’s high fat and high carbs and then they have to cut back on exercise or gym classes because of budget cuts.
Exercise America! It’s as simple as just walking a mile a day. There is no great need to join a club; everyone can do it.
Feb 25 2011
I disagree with most posts. Those that say the processed or refined food is the problem should put pencil to paper and calculated the cost or even ability to feed the nation of 303 million on non grains and non processed foods. I have not personally done the math but you are not going to feed 303 MM mouths on heirloom tomatoes and spinach salad. Those that are saying that poor people can’t eat healthfully need to calculate the cost of a diet of dried beans, rice and frozen vegetables. You can eat very healthfully on very low costs. The studies that report that old tired myth always uses very high cost items like fresh blueberries VS spam. That is not fair and only gives lower income people yet another excuse to abuse their bodies. The only way to solve obesity will be doing some harsh and some will say degrading things that make it less comfortable to be obese. How about putting people on the scales before a doctor’s appointment and having medical reimbursement be commensurate with their BMI? Or, if they cannot pay, at least have them spend a few hours on a treadmill to generate electricity to go towards their medical bill (obesity is caused by excess energy storage that becomes physiologically dysfunctional). OK I am maybe kidding about that one. Maybe. The problem is that, in an effort to be compassionate, we actually enable overeating. It is a choice.
Feb 25 2011
Fast food portions are only one side of the obesity triangle. The other two are availability of healthier alternatives and personal responsibility.
The correlation between fast food density and obesity is not straight forward. Sure, America’s urban centers are overpopulated with fast food & take out restaurants. But, at the same time, they are littered with bodegas and low end supermarkets that carry processed foods without the balance of organic or all-natural alternatives. The quality of produce in inner city supermarkets has consistently been low. All this contributes to an alarming incidence of obesity.
On the issue of personal responsibility, America has failed to educate the people who feed our children. Most inner city kids come home to an empty house. While a small few may have learned to cook for themselves, the majority rely on snacks and prepared foods (think hot pockets) for nourishment until a parent gets home. And in single parent families, ordering takeout may be the only viable alternative after a long day.
I don’t defend the role of fast food in America’s obesity crisis. But I don’t believe penalizing them will reverse the obesity rate. Instead, I would propose a revised Home Economics program in our public schools and tax incentives to bring high end retailers to fill the gap in America’s nutritional deserts. A pragmatic approach is needed here. Pointing the proverbial finger only tears this country even further apart than it already is.
Dec 30 2011
I think that fast food does make us fat, but it is the person’s choice to buy the fast food. Fast food is not an addiction. It’s the persons choice!!!