As with most psychology experiments, the study involved lying to people. Subjects were given a milkshake on two separate occasions but were told that one contained a whopping 620 calories and the other had a more sensible 140 calories. In reality, both shakes were the same – right in the middle at 380 calories.
Before and after each test, the researchers monitored the subjects’ ghrelin levels as a measure of how satisfied they were. Ghrelin – the hormone which triggers hunger – increases and spikes before meals, then drops off after people eat. If the calorie content were all that mattered, there would be no difference in reactions to the two shakes. But there was:
Results: The mindset of indulgence produced a dramatically steeper decline in ghrelin after consuming the shake, whereas the mindset of sensibility produced a relatively flat ghrelin response. Participants’ satiety was consistent with what they believed they were consuming rather than the actual nutritional value of what they consumed.
What should we make of the finding (besides a continued fascination with the placebo effect)? For one thing, it reinforces the notion that our stomachs are very crude sense organs which aren’t precise or accurate at judging how much food they need.
For anyone trying to achieve (or maintain) a healthy weight, the dynamic makes it tougher to diet. The conscious decision to eat ‘sensible’ food motivates our bodies to demand more calories. What a frustrating situation!
Patrick at Discoblog toys with a creative solution:
It definitely suggests some new approaches to dieting, like berating yourself for eating celery sticks in an effort to make them seem more luxurious and satisfying. But it’s not clear if lying to yourself is as effective as having other people lie to you. And believing that you are constantly eating poorly might have other psychological side effects, one supposes.
I agree, it probably doesn’t work as well to lie to yourself (and nobody will be able to convince me that celery sticks are fatty treats). But we can draw a useful tactic that doesn’t require deception. Instead of applying the study’s findings when we eat light food, keep it in mind when eating dessert. Next time you want a rich slice of cheesecake, look up how many calories it has! According to the study, focusing on the fact that the slice has 50% of your recommended calories will make you feel more satisfied eating less of it.
What I’d like to see is a study that’s honest about the number of calories but emphasizes different ingredients to foster that ‘indulgent’ mindset. Would our bodies react differently to drinking a “300-calorie fruit milkshake” compared to the same one described as a “300-calorie shake with bananas, heavy cream, vanilla extract, and pure cane juice”?
If that works, we can help our friends and families by focusing attention on the fattiest, sweetest, and tastiest part of a dish. Next time Julia is willing to make those delicious-looking blintzes again, sign me up. I can eat one as she tells me about the heavy cream that went into the homemade ricotta.
[UPDATE] I’m looking a little deeper into what exactly was being measured – the abstract and researchers said “Participants’ satiety was consistent with what they believed they were consuming rather than the actual nutritional value of what they consumed.” but news sources report this as well:
The study also didn’t find that the larger drop in ghrelin in those who drank the indulgent shakes was accompanied by a larger drop in hunger levels, a finding that the researchers couldn’t fully explain. “We may not have used a reliable measure of hunger,” says Crum. “My sense is that hunger levels should have changed.”
I had assumed that the participants’ satiety was the same as their remaining hunger – but those two quotes seem at odds at first glance.