LOS ANGELES — Adults with obesity who underwent anodal transcranial direct current stimulation consumed fewer calories from soda and fat and experienced greater weight loss vs. those who underwent cathodal stimulation, according to study findings presented at ObesityWeek.
In a double blind, randomized, placebo-controlled, parallel study, Marci E. Gluck, PhD, of the National Institute of Diabetes and Digestive and Kidney Diseases in Phoenix, and colleagues also found that those who underwent positive transcranial direct current stimulation (tDCS) aimed at the left dorsolateral prefrontal cortex (DLPFC) tended to consume fewer kilocalories per day on average, whereas those who underwent a sham procedure experienced no differences.
Marci E. Gluck
Gluck and colleagues analyzed data from nine healthy adults with obesity (six women; mean age, 42 years) who participated in two studies for 9 days in an inpatient facility. For the first study (mean BMI, 38 kg/m²), participants received either cathodal or sham tDCS (2 mA; 40 minutes) on 3 consecutive mornings after 5 days of a weight-maintaining diet. The cohort was then permitted to eat without restrictions for 3 days from a computerized vending machine — stocked with foods rated favorably on food preference questionnaires — that recorded energy intake. Participants were weighed daily.
Researchers discovered after the study was already underway that positive and negative stimulation leads had been reversed since the beginning of the study, resulting in placement of the active cathode over the left DLPFC, Gluck said during her presentation. Researchers halted the study and analyzed the data; no adverse effects or effects on weight or food intake were found.
For the second study (mean BMI, 34 kg/m²; mean follow-up time between study visits, 2.9 years), researchers repeated the original study design but used either anodal or sham tDCS on the same cohort. The study design was then modified to compare the effects of anodal vs. cathodal stimulation on food consumption and weight change between the two studies, with the sham group serving as a control. Researchers used paired t tests to determine differences within each group between the first and second study.
Participants who received anodal tDCS consumed fewer kilocalories per day (P = .07) and a smaller percentage of their weight-maintaining energy needs (P = .11) vs. cathodal stimulation, and consumed fewer kilocalories from fat (P = .03) and soda (P = .02), but not from carbohydrates (P = .13) or protein (P = .69).
Participants who underwent anodal tDCS also experienced a mean weight decrease of 0.2% after the 3-day energy-intake measurement period; those who underwent cathodal stimulation experienced a mean weight increase of 0.6%. Participants with a sham procedure experienced no weight changes, according to researchers.
“Our results, in combination with previous work, point to a role for the [left] DLFPC in energy intake and body weight regulation,” the researchers wrote. “However, the mechanisms that mediate this association are not clear ... Anodal tDCS over the [left] DLFPC could have reduced food intake by simultaneously suppressing food cravings and facilitating choices requiring delayed gratification.”
Results of the study also were published in Obesity. – by Regina Schaffer
Gluck, ME, et al. Noninvasive neuromodulation targeted to the lateral prefrontal cortex induces changes in energy intake and weight loss in obesity. Presented at: ObesityWeek; Nov. 2-6, 2015; Los Angeles.
Gluck ME, et al. Obesity. 2015;doi:10.1002/oby.21313.
Disclosure: The researchers report no relevant financial disclosures.