• Will people eat less if you ask them to?

    There are times I wish I had a macro for the beginning of a post on obesity. Some way to say obesity is bad, obesity is prevalent, and nothing seems to work. You know the drill.

    But there’s a new study in Health Affairs that was surprisingly promising:

    We performed three related field experiments at a single fast-food restaurant to determine whether these reported sentiments could be translated into a strategy to alter calorie consumption. All of the experiments addressed three important elements of eating behavior.

    First, do people spontaneously request smaller portions—that is, even if smaller portions are not specifically noted as an option on a menu or signage? Second, do people accept explicit spoken offers to take smaller portions in order to reduce calories? Third, does taking a smaller portion of one meal component lead to indulgence in other meal components, so that the calorie “savings” from downsizing are immediately lost?

    Each experiment addressed an additional question. In experiment 1, we explored whether offering a nominal (twenty-five-cent) discount for downsizing would result in more customers’ accepting the offer than offering no discount. In experiment 2, we examined whether offering an opportunity to accept a smaller portion would be more effective than providing calorie labels in encouraging moderation. In experiment 3, we investigated whether downsizing appealed only to customers who would otherwise have thrown away uneaten food, thereby affecting calories ordered but not calories consumed.

    Let’s start with experiment 1. First, they measured how many customers would spontaneously request a smaller portion of a high-calorie, high-starch side dish. Not surprisingly, only 1% did. But if customers were asked, on the other hand, one third accepted the offer, regardless of whether a discount was offered. What’s more, those that did downsize did not compensate by up-sizing any other portions of the meal. Those that downsized ordered significantly fewer calories, 100 fewer on average.

    Experiment 2 compared menu labeling of calories (which I’ve discussed somewhat cynically a  number of times) with asking people to downsize. This is when it gets a bit crazy. First of all, significantly more customers accepted the offer to downsize their meal before calorie labeling was provided than after (21% versus 14%). In other words, menu labeling may have made them less likely to downsize. Additionally, in the group without menu labelling, when asked, those who downsized saved an average of 76 calories. With the menu labeling, they saved fewer (although not statistically significantly fewer) calories, only 17 on average. Not only did menu labeling not help; it may have made things worse.

    Experiment 3 tried to tease apart the difference between what was ordered and what was eaten. It’s possible that people who didn’t downsize left more on their plates than those who did, meaning that ordering fewer calories didn’t lead to less calorie consumption. But those who rejected the offer to downsize (and therefore had more food to start) had no less left over than those who did downsize their orders. In other words, those who accepted the offer to downsize actually consumed fewer calories.

    Granted, this is one study of Chinese fast food. I’m encouraged by the results, though. I’ve always acknowledged the tension between a need for better policy and the pushback against “nanny-state” solutions. But in this intervention, just asking people if they would like to eat less resulted in a decent number of people agreeing to. It worked better without menu labeling than with it. And it was entirely voluntary.

    Asking people to supersize works. Apparently asking them to downsize does, too. We should try that more often.

    Share
    Comments closed
     
    • Yes, but are you proposing we mandate “down-sizing” options at fast food restaurants? Seems like a logistical nightmare – what prevents a chain from increasing their normal portion? And doesn’t that raise much stronger concerns government intervention?

      Calorie-labeling might be less effective, but it’s also much less intrusive.

      • Who said anything about mandating? This was voluntary, and didn’t deprive anyone of money. They just asked people if they’d like less, and many did. They charged the same amount for less food. Restaurant lost no money, and no one complained.

        How is this intrusive or a logistical nightmare?

        • I understand the study was voluntary, and you certainly didn’t mention any kind of mandate, but I just assumed that you were advocating for this study to somehow be scaled up. I apologize for the misunderstanding, but I’m surprised that you think it could be scaled up voluntarily.

          Why would fast food restaurants give up large portions and “super-sizing” voluntarily? “Super-sizing” is a very profitable venture, as you can make a customer pay 25 cents more for 5 cents more worth of product. Subway’s “$5 Dollar Footlong” campaign (essentially a super-sizing campaign) is one of the most profitable marketing promotions in recent history. The same logic applies to “down-sizing.” Why would restaurants voluntarily offer a 25 cent discount when the extra food cost 5 cents to make? They’re giving away money.

          Now, the study did suggest that people would voluntarily down-size even if restaurants did not drop the price. However, I suspect that this finding would not scale up to the real world. The reasons for my suspicion are two-fold:
          1) Restaurants already have an incentive to keep portion sizes down for a given price – it costs less to produce. If a large number of people are receptive to smaller portions, why haven’t restaurants just decreased portion size across the board?
          2) Competition effects, where a restaurant that attempted to offer smaller portions would be seen as cheating or scrimping on its portions, and consumers would choose different restaurants.

          Of course, it’s easy for me to sit here and lob criticisms, and hard to scale up effective public health interventions. I’d be thrilled to be proven wrong, and for someone like Michelle Obama, as part of her national fitness campaign, to convince a fast food chain to offer a voluntary “down-size” option. I’m just not holding my breath.

          And finally, with this set of studies alone there seems to be more evidence for the effectiveness of down-sizing compared to calorie labeling. But calorie-labeling has the advantage of being much easier to implement on a nation-wide scale.

    • “There are times I wish I had a macro for the beginning of a post on obesity. Some way to say obesity is bad, obesity is prevalent, and nothing seems to work. You know the drill.”

      🙂 hahaha, I’ve had the same thought.

      This is why I roll my eyes at the first paragraph in almost every paper I read about obesity/diabetes. DID YOU KNOW AMERICANS ARE FATTER THAN THEY USED TO BE!?!?!?

    • Didn’t Fridays offer smaller portions for less money at one point? I don’t know if it reduced calorie intake, but I don’t think it was successful business-wise.