You'd think, with the ugly truth at last laid out before them courtesy of the new labeling law, California's restaurant diners would alter their behavior. That's a no-brainer, right?
Certainly, health experts hope that clearly displayed nutrition facts will encourage folks to straighten up and order right. But the evidence so far is inconclusive.
It doesn't help that restaurant menu labeling is still fairly new — the first law went into effect in New York City in July 2008 — so the bulk of what's known comes from simulations that may not mirror real-life dining behavior.
Some of what we know:
• A study published in January in the journal Pediatrics reported that mothers made better choices for their children when provided with calorie numbers but didn't make those same decisions for themselves. In the randomized, controlled study, 99 parents of children ages 3 to 6 were given a McDonald's menu and asked to choose what they might order, just as if they were in the restaurant.
Parents who received menus with calorie information ordered an average of 102 fewer calories for their children than a control group not given that information. But there was no calorie difference between the two groups in what parents ordered for themselves.
"Anecdotally I know that people do want what's best for their children," says study author Dr. Pooja Tandon, a pediatric researcher from Seattle Children's Research Institute. So why don't they make better choices for themselves? Tandon isn't sure. "Maybe in other areas of health, like smoking, they may be more inclined to be healthier when they know it's going to affect their children."
• Researchers at Stanford University studied customer habits at some Starbucks locations in New York City from January 2008 to February 2009 (straddling the period when the city's menu labeling laws went into effect). Average calories per transaction decreased by 6% after the change, almost all of it related to food, not beverages. Food calories per transaction decreased 14%.
Of the calorie decrease, 75% came from buying fewer items and 25% from choosing lower-calorie items.
• Posting calories didn't seem to change the habits of fast-food-chain customers in New York City, according to a different study. Published online in October in the journal Health Affairs, it surveyed 1,156 adults eating at fast-food restaurants in low-income, minority New York City neighborhoods. About half of the people noticed the calorie labeling, and of those, almost 30% said the information influenced what they selected. Most said they made more healthful choices because of it.
But when researchers examined receipts, they detected no difference in calories compared with people surveyed in an area of New Jersey where the law didn't apply and nutrition information wasn't available.
• A study published online in December in the American Journal of Public Health found that, though nutrition labeling helps, it may not be enough. In the study, 303 people eating dinner were randomly assigned to choose from a menu that had no calorie information, one that had calories, or one that had calories plus prominently displayed information on the recommended daily calorie intake for an average adult.
Those in the two groups with calorie information ordered 14% fewer calories overall at dinner than those without it. But the group supplied with just the calorie information made up for being careful at dinner — they consumed more calories later in the evening and ended up eating as much as the no-calorie-information group.
Those who got information on daily recommended calorie intake as well, however, ate an average of 250 fewer calories during dinner and after than either of the other two groups.
Adding the daily calorie information was an eleventh-hour decision, says Kelly Brownell, one of the study's authors and director of the Rudd Center for Food Policy and Obesity at Yale University. "It occurred to me that people may not know what calories mean. If a burger is 800 calories, is that a lot or a little? We thought that if we provided some reference points, it might make a huge difference."