As a registered dietitian, I’ve always relied on published scientific research to underpin the diet and nutrition advice I give to clients and the public. Some of that advice has come from the conclusions of a handful of well-respected and well-published researchers, scientists whom I’ve followed for much of my career.
So, you might image the jolt I felt when one of those scientists recently fell from academic grace. Earlier this month, Dr. Brian Wansink, professor and director of Cornell University’s Food and Brand Lab, resigned after ongoing concerns over unethical research methods.
You might not be familiar with his name, but, chances are, you’ve heard about a few of his headline-grabbing studies on mindless eating – how subtle environment influences, such as the size of a food package, the shape of a glass, or grocery shopping on an empty stomach, can trigger overeating.
In December, 2012, I devoted my Globe and Mail column to preventing holiday overeating by using many of Wansink’s tactics to bypass under-the-radar overeating pressures. I advised readers to serve meals on smaller plates, pour caloric drinks into tall, skinny glasses and keep sugary, fattening treats hidden from plain sight.
Turns out, some of his studies were flawed due to questionable data reporting, problematic statistical techniques and failure to properly document research results.
On Sept. 19, the Journal of the American Medical Association retracted six of Wansink’s papers, resulting in a total of 13 retractions to date. One day later, Cornell University’s internal year-long investigation concluded that Wansink committed academic misconduct.
Do I feel betrayed? Sure, I do.
Why would I suspect that research findings from a world-renowned eating behaviour expert, published in prestigious, peer-reviewed journals, are not what they seem? (And if I did, I certainly don’t have the statistical wherewithal to reanalyze the data to confirm or dispute the findings.)
According to a 2011 report in the journal Nature, retractions of flawed scientific papers are on the rise, thanks to regulatory bodies and software systems that can detect methodological mistakes.
Even so, does the retraction of Wansink’s papers render his concepts about mindless eating meaningless? I don’t think so. At least, not all of them.
The “plate-size-effect” – the idea that identical food quantities appear larger when served on a smaller plate has been studied by many researchers. Some experiments, but not all, have reported that serving food on smaller plates led to a reduction in food intake.
A 2017 study from New Zealand revealed that food presented on a small plate (23-centimetre diameter) was associated with a higher satiation (i.e., feeling of fullness) score than the same amount of food served on a large plate (27-cm). When shown photographs of identical food portions on small and large plates, participants also estimated they would eat less food on the small plate versus the larger one.
Research from the United Kingdom published online in August found that eating with a smaller spoon reduced bite size, eating pace and food intake in men.
There are other potential overeating triggers besides the size of dinnerware and cutlery. Many studies have found that eating while distracted – whether watching TV, surfing the internet or listening to a podcast – leads to eating faster, eating more calories and feeling less satisfied after eating.
It’s thought that distraction reduces our sensitivity to physiological and sensory cues that signal us to stop eating.
Distracted or not, previous research has shown that people who eat quickly versus slowly eat more calories. One study of 4,140 adults found that those who wolfed down their food – and ate until they felt full – were three times more likely to be overweight than their peers who ate slowly and modestly.
Scientists believe it takes at least 20 minutes for appetite-related hormones to kick in after eating a meal.
I will continue to offer clients strategies to set up their eating environment in a way that helps prevent overeating and, at the same time, encourages mindful and enjoyable eating.
That may mean serving dinner on a luncheon-sized plate, keeping tempting treats hidden and healthy snacks easily accessible, unplugging and sitting at the table to eat, pausing between bites, or assessing one’s hunger level before, halfway through and after finishing a meal.
I am disheartened by the fact that Prof. Wansink committed academic and research misconduct. But, at the same time, I’m grateful for the insights about mindless eating he brought to our attention.
Leslie Beck, a Toronto-based private practice dietitian, is Director of Food and Nutrition at Medcan.