If your waistline has gotten a bit thicker over the last decade, you’re not alone. The majority of people in North America (68.8%), are now either overweight or obese. But it’s not your fault.
We have a natural tendency to crave foods containing high amounts of sugar and fat, since they provide our body with instant energy. The only problem is the ubiquity of these foods in our modern environment. But why are some people better able to withstand their lure than others?
A scientist named Schacter has provided us with an interesting answer to this question. He conducted a number of experiments in the 1960’s and 70’s to examine human eating behaviour, and found that thin people follow different eating cues than everybody else. According to Schacter, thin people use hunger pangs as a guide to how much they will eat, whereas overweight or obese people follow external cues about the food itself, such as the way it smells, or looks, or tastes. In our modern, media-saturated world, guess whose appetites have been easier to manipulate?
One external sensory cue which has been heavily manipulated in our modern culture is serving size. Studies have shown that people tend to empty their plates, regardless of how much food is on it. This means that food served on a larger-sized plates, will be eaten just as readily as a smaller amount of food on a small plate. What is crucial here is that most people don’t even realize they’re eating a different amount of food.
According to surveys, yogurt containers in North America are 82% larger than those in France, where the tendency towards obesity is much lower. Candy bars in North America are also 41% larger and soda cans are 52% larger. When we try to evaluate why French people are so much thinner than North Americans, we tend to fixate on what they eat, rather than how much. It’s very likely that, despite our best intentions, we simply eat more. The bigger serving sizes in grocery stores and in restaurants may be largely to blame for this. The popularity of buffet restaurants, which encourage over-consumption, also play a part.
Schacter’s studies also showed that people tend to eat more when they are with friends or loved ones, rather than alone. This is why couples tend to gain weight once they start living together and share meals. Again, the crucial fact here is that we don’t even realize we are eating more food. If asked, we assume we have eaten the same amount of food as usual. Yet studies show that we take hunger cues from the people with whom we eat, and if they eat more, we’ll eat more too. (Vartanian et al., 2008)
Of course, stress is an important factor in any discussion about diet. Studies show that 81% of people experience a change in their appetite when stressed, with 62% of people eating more than usual. When stressed, we also tend to make poorer food choices, indulging in high calorie foods, like cake, doughnuts, or burgers, rather than healthy, low calorie foods like fruits and vegetables. And because these high calorie foods increase feel-good neurotransmitters like serotonin in our brains, a cycle is created where we crave the same foods again the next time we’re stressed. We become like Pavlov’s dogs: every time our mood needs a lift, we feel a craving for the same foods that improved our mood in the past.
Heavily restricting our food intake doesn’t seem to help much. In a study done in 2003, girls whose parents placed them on a heavily restricted diet showed a greater tendency to binge on the restricted foods when given the chance, even if they weren’t hungry. Girls whose parents did not restrict their eating had a normal respect for sensations of hunger, and ate only when necessary (Birch, Fisher, & Davidson, 2003).
If none of this has convinced you of how elastic, and easily manipulated our appetites are, this final study will. In a study done in 2012, patients with amnesia were offered a second and then a third meal, each one 10-30 minutes after the last. No matter how much food had been eaten previously, participants continued consume each meal in succession. Since the patients couldn’t remember when they had last eaten, they readily ate the next meal whenever it was presented to them. Presumably, their stomachs were still full, but that didn’t stop them from continuing to eat whenever more food was offered. A second study showed similar results in people who didn’t have amnesia. These two studies are damning evidence for easily our natural hunger cues can be ignored.
With all these psychological cues working against us, how are we to win the battle with the weight scale? To a certain extent, it should be helpful just knowing how badly the cards are stacked against us. And now that we know all the ways our brain can be tricked into over-eating, we can make plans to thwart those natural tendencies. It’s also important to be gentle and forgiving of ourselves if we happen to over-indulge when we shouldn’t. We may not be able to win every battle, but with enough awareness, we can still win the war.
About the author: Rebecca Wong has an honours degree in English Literature from the University of Waterloo, and has been working in the herbal business since 2000. She has received her training in acupuncture and herbalism from respected authorities Paul Des Rosiers and Vu Le at the Ontario College of Traditional Chinese Medicine in Toronto, and Michael Tierra at the East West Herb School in California.