The other day, I witnessed a diet-binge in action. My colleagues had decided to celebrate November’s employee birthdays with a dozen pies, set out for the taking in our lunchroom. As I walked in, I saw a co-worker digging ferociously into one of four pie wedges, piled on her paper plate. Without looking up, mouth full of chocolate mousse, she announced that she had just finished her “diet” and could now eat “whatever and whenever (she) wanted.”
I thought about all those pies of birthdays past, all the treats of holidays present and all the diets of New Year’s future. These food schemes will be broken by February, lamented in March and resumed by spring – just after the parade of swimsuit advertisements.
Coincidentally, I stumbled across a recent study that explains the diet-binge cycle. It’s about brain chemistry and stress -- not behavior and lack of willpower.
Pietro Cottone and colleagues at Scripps Research Institute recreated a diet-binge-diet cycle in rats. The researchers fed one group of rodents alternating cycles of regular chow (5 days) and sweetened, chocolaty chow (2 days). A second group of rats ate only regular-tasting food throughout the entire experiment.
After eating sweets, the diet cycled rodents were less motivated to eat regular chow and ate less of it, as might be expected. But a surprise came when the now-dieting rodents became more sensitive to anxiety-provoking situations and avoided them. When the animals returned to sweets, they binged -- and their anxiety-related behaviors temporarily quelled.
This diet-binge anxiety loop played out in the animals’ brains. Diet-cycled animals boosted levels of stress-related molecule called corticotropin-releasing factor (CRF) by 5 times in an area of the brain known as the central amygdala, which is involved in fear, anxiety, and stress responses. Only when the diet-cycled group was fed sweet food did CRF levels return to normal. Temporarily.
The message is that the diet part of the diet-binge cycle creates stress and anxiety in the brain, which in turn fuels the urge to binge. Binging temporarily relieves the brain’s perception of stress. But it is followed by a state of withdrawal – characterized by lack of motivation and hypersensitivity to stress.
"People will often say they are eating bad foods or fail a diet because they 'are stressed,'" says author of the study Eric Zorrilla, at Scripps Research. "Our findings suggest that intermittently eating sweet food changes the brain's stress system so that you might feel stressed, even though nothing that terrible has happened.”
How to stop it? Well in the study, researchers gave diet-cycled rats a compound called R121919 that blocks a receptor for CRF. The compound curbed the bingeing on sweet chow, upped the animals’ consumption of regular chow and dampened the anxiety-associated behaviors.
And in people? We may have to wait until researchers develop drug therapy to escape an unhealthy cycle of eating extremes, be it anorexia, bulimia or any other eating disorder. In the interim, know that diet cycling activates the brain's stress system, which in turn is linked to emotional disorders. And those are likely exacerbated by the holiday season, anyway, without the help of bad eating.
Eat well. Eat balanced. Feed your emotions with self-care, not food. The goal is to limit stress, not heighten it with cycles of overload and deprivation.
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