Stress, NPY, and Obesity….

I always wanted to be one of those people who lost weight when stressed. Unfortunately, I could pretty much track my stress levels as a function of how my weight fluctuates: more stress = more me. Like many Americans, Roger and I found that we had added more than a few pounds. I refuse to post the before pictures–but here we are after 8 months of dieting with Jenny Craig. Roger wants to lose about 30 more, but I’m within about 5 pounds of my goal.

Zofia Zukowska of Georgetown University and her colleagues have learned more about the relationship of stress and obesity by observing the responses of mice to a combination of stressors (cold water baths or the presence of an aggressive mouse) and a diet high in fat and sugar [1]. Neither stress alone nor the high calorie diet alone led to an increase in the abdominal fat of the mice, but the combination of both did. Simultaneously, levels of neuropeptide Y (NPY), a hormone intimately linked to the initiation of feeding behaviors, also increased. Mice genetically engineered to lack NPY receptors did not show increases in fat, nor did mice to whom an NPY antagonist was administered.

Although it is likely that NPY will receive further attention in the fight against obesity, its activity is so important in many systems that avoiding side effects will be tricky. Something has to happen. On our recent road trip to get Karen settled at the University of Tennessee, we were shocked to see how big Americans were becoming.

Our family continues to have good results using Jenny Craig. It’s idiot-proof. You eat what they give you, and you lose weight (four of us have lost a collective 210 pounds in 8 months). A recent study by Cheryl Rock and her colleagues at UC San Diego reported that women using Jenny Craig were far more successful in weight loss than women pursuing a diet on their own [2]. My guess is that in the near future, supermarkets will offer portion controlled meals for people who want to control weight–maybe color-coded for your calorie level.

1.  L.E. Kuo et al., “Neuropeptide Y acts directly in the periphery on fat tissue and mediates stress-induced obesity and metabolic syndrome,” Nature Medicine, published online July 1, 2007.

2.  C.L. Rock et al. (2007), “Randomized trial of a multifaceted commercial weight loss program.” Obesity, 15, 939-949.