Charting Cerebral Blood Flow in Anorexics with Binge-Purge Behavior
Reprinted from Eating Disorders Review
November/December 2000 Volume 11, Number 6
©2000 Gürze Books
Is It Possible to Control Weight?
An international epidemic of obesity has led health officials to encourage people to avoid gaining weight and if they are overweight to lose weight. Is anyone listening and, if so, can anyone really successfully control his or her weight?
The results of a 3-year community based study were not too encouraging (Int J Obesity 2000;24:1107). The subjects, 54 men and women from 20 to 45 years of age, were assigned to one of three treatments. Half were placed in a no-contact control group, a fourth received educational materials through monthly newsletters, and a fourth were given educational materials and an incentive for participating in the study. The intervention groups received the same educational and behavioral messages, including monitoring their weight, eating 2 servings of fruit and 3 of vegetables daily, reducing intake of high-fat foods, and walking for at least 20 minutes 3 times a week.
Only 1 in 4 avoided weight gain
More than half of the subjects gained weight over the first 12 months, and only 1 in 4 (24.5%) successfully avoided gaining weight over the 3 years. Fewer than 1 in 20 (4.6%) successfully lost weight and maintained the loss.
General public health efforts to prevent weight gain are extremely important, according to the authors. Their findings suggest that without much greater efforts to promote and support weight control, most people won't be able to avoid weight gain and very few will manage to lose weight. Without greater public health efforts, the worldwide epidemic of obesity will continue to gain momentum.
Tetsuro Naruo, MD, and co-workers at Kagoshima University, Japan, have used the technical powers of single photon emission computed tomography (SPECT) to chart distinct changes in cerebral blood flow among patients with anorexia nervosa (Am J Psychiatry 2000; 157:1520).
Dr. Naruo and colleagues studied 7 female patients with purely restrictive anorexia, 7 female patients with anorexia nervosa and habitual binge-purge behavior, and 7 healthy female controls. The women were asked to visualize a piece of custard cake for 10 seconds and then to imagine themselves eating the cake for 5 minutes. SPECT Scans were made before and after the women visualized themselves eating the cake.
After visualization, women with habitual binge/purge behavior had a significantly higher percentage of increased cerebral blood flow in the inferior, superior, prefrontal, and parietal regions of the right brain than patients with purely restrictive anorexia nervosa and the healthy volunteers. Patients in the first group also had the greatest apprehension about food intake.
Dr. Naruo and his group think that neural pathways involved in the recall of events in the memory process may have an important role in binge eating and purging among anorexic patients. Their findings also suggest a close association between neural network activation and episodic memory retrieval. The fact that specific activation of cortical regions of the brain plays an important role in perception and memory suggests an association between habitual binge/purge behavior and the cerebral recognition process.