The term "craving" hardly does justice to that overwhelming feeling that you just can’t go on without a taste of your favourite food.
Must… have… chocolate. Must… eat… ice cream. Can’t… stop… eating pizza.
Cravings are a fact of life: almost everyone has, at some time, been seized by a strong and specific urge to eat. While men go for salt/fat combinations like crisps and tortilla chips, women tend to crave sugar/fat combinations – and, no surprises here, chocolate is number one on the cravings list.
It seems like there’s nothing to do but either fight off the cravings and obsess about ice cream all day, or give in to them. Mostly, we give in, telling ourselves that it’s all down to biology and there’s really nothing we can do about it.
But in humans, hunger and eating are strongly influenced by context. That seems to be true of cravings, too. Even though the desire feels deep-down and basic, habit and conditioning seem to have a lot to do with it.
Research at University College, London shows that the yen for tasty treats may, indeed, be an acquired habit.
Jay Gottfried and colleagues at University College London, trained volunteers to crave vanilla ice cream and peanut butter at the sight of computer images. While smelling the odours, volunteers showed heightened activity in areas of the brain called the amygdala and the orbitofrontal cortex - part of the brain's reward circuit.
However, after the subjects had been allowed to eat their fill of the foods, the smells became less enticing to them and the images did not produce a hunger response.
Psychologist Leigh Gibson, at UCLs Health Behaviour Unit, studies appetite and food choice. Gibson rounded up several dozen student volunteers to find out whether people could be “trained” out of their cravings. The students in the study ate half a bar of milk chocolate twice a day for two weeks. Half ate their chocolate ration 15 minutes after finishing a meal; the other half waited at least two hours after a meal before having the sweet. The students filled out a diary rating the strength of their cravings and the appeal of the chocolate by answering questions like: “If any amount of chocolate was available, how much would you want to eat right now?” Volunteers included both people who loved chocolate and those who were indifferent to it.
After two weeks, the volunteers who had been eating the chocolate on an empty stomach reported that their yearn for chocolate was stronger. By contrast, the students who had been eating the chocolate on a full stomach said their cravings were much weaker. That was true for both cravers and non-cravers.
What’s more, people who’d been eating the chocolate when full actually said that it now seemed a bit less pleasant to the taste. It seems that by eating the sweet when they weren’t hungry, the volunteers had trained themselves to like it less.
“I do believe that one should be able to retrain one’s appetite, or reduce one’s craving, for particular foods by eating them only when not hungry,” says Gibson. “However, this may only apply to foods that are relatively energy rich.” He tried a similar experiment with dried fruit bars and got very different results, suggesting that lower-calorie foods may not have the same effects.
But Gibson points out that most commonly craved foods - ice cream, pizza, cake - are also very rich and energy-dense. “It’s a lot easier to walk past the greengrocers or fruit stall without being tempted than to walk past the confectionery counter or cake shop, isn’t it?”
The wonderful implication: cravings for rich, fatty foods might be conquerable. You don’t have to be a slave to your appetite!
The bottom line, he says, is that it’s a good idea not to eat foods you are trying to avoid or eat less of when you are very hungry. “The trick is to eat frequently enough to avoid strong hunger, but without eating too many calories in total.” Easier said than done, he admits - but his finding may explain why people who “graze,” or eat small amounts throughout the day, are often healthier and slimmer.