The Problem with Dieting

How dieting creates food addicts.

Posted Nov 17, 2009

A recent study showed just how chronic dieting can turn someone into a food addict.

Bad news for yo-yo dieters this week: according to a recent study, cycles of feast and famine can create fast-food junkies–at least in rodents. The researchers put rats on a cyclic diet of 5 days of standard rat chow, followed by 2 days of the equivalent of rat fast food (high fat, high sugar, highly delicious). In other words, a compressed version of most dieters' swings between self-control and indulgence.

The first thing they observed is that it didn't take long for the rats to develop a clear preference for the unhealthier diet. When put back on a standard diet, they showed signs of anxiety and reduced pleasure from (or even refusal to eat) the standard chow. When the preferred food was available again, their anxiety calmed down, but they overate.

After 7 weeks, the researchers took a look at what this diet had done to the rat's brains. They found increased gene expression for corticotropin releasing factor (CRF) in the rats' amygdalas–that is, the brain was resetting itself for higher levels of stress. This is the same pattern of brain changes observed during withdrawal from alcohol or other addictive substances. Other research has demonstrated that this neural stress response triggers cravings and relapse among the substance-dependent.

In effect, by making the unhealthy food temporarily unavailable, the researchers created food addicts. Food might not be addictive on its own, but prohibiting it can set off a cycle of anxiety, craving, and overconsumption that for all purposes looks like addiction. There's no reason to believe that the food itself was the problem in this study, but the anxiety induced by restricting access to it.

Another study offers hope for ending the cycle. Researchers at Laval University in Québec, Canada have been following the benefits of a unique weight control intervention for over a year. This intervention, called "What about losing weight?" emphasized the possibility of being "healthy at every size."

Rather than making food restriction and weight loss the goal, the intervention emphasized positive things participants could to improve their health: good nutrition (what TO eat, not what NOT to eat), enjoying physical activity, and listening to their bodies. It also taught strategies for appreciating your body as it is now, regardless of size.

Participants in the study were overweight or obese women who had likely entered the study as chronic dieters. By the end of the study, they showed significantly less "food disinhibition," or losing control around food during stress, celebration, or other situations that trigger overeating.

At the 1-year follow-up, two-thirds of participants had lost weight, despite the interventions' explicit focus on positive behaviors, not trying to reduce food intake or lose weight. Compare this to the quick weight loss followed by weight gain that a typical diet leads to. Participants who developed the most "flexible" restraint (as opposed to the rigid restraint of most dieting strategies) were the most likely to maintain a weight loss.

From the first forbidden food (a very tempting apple), prohibition has led to problems. This study shows that focusing on positive steps, not self-denial, can make you less likely to succumb to food-related stress and anxiety. If you want to improve your overall self-control, and regain control around food, you may need give up the ideal of perfect control.

Studies cited:

1. Cottone P, Sabino V, Roberto M, et al. (2009). CRF system recruitment mediates dark side of compulsive eating. Proc Natl Acad Sci U S A. 2009 Nov 9. [Epub ahead of print].

2. Provencher V, Bégin C, Tremblay A, et al. (2009). Health-at-every-size and eating behaviors: 1-year follow-up results of a size acceptance intervention. J Am Diet Assoc, 109(11),1854-1861.


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