Our study implies that the application of anodal direct currents to the right DLPFC represents a promising option for reducing both caloric intake and appetite in humans. This trial was registered at the German Clinical Trials Register (www.germanctr.de) as DRKS00005811.

Background The question of whether there is daytime time variation in diet-induced thermogenesis (DIT) has not been clearly answered. Moreover, it is unclear whether a potential diurnal variation in DIT is preserved during hypocaloric nutrition. Objective We hypothesized that DIT varies depending on the time of day and explored whether this physiological regulation is preserved after low-calorie compared with high-calorie intake. Design Under blinded conditions, 16 normal-weight men twice underwent a 3-day in-laboratory, randomized, crossover study. Volunteers consumed a predetermined low-calorie breakfast (11% of individual daily kilocalorie requirement) and high-calorie dinner (69%) in one condition and vice versa in the other. DIT was measured by indirect calorimetry, parameters of glucose metabolism were determined, and hunger and appetite for sweets were rated on a scale. Results Identical calorie consumption led to a 2.5-times higher DIT increase in the morning than in the evening after high-calorie and low-calorie meals (P < .001). The food-induced increase of blood glucose and insulin concentrations was diminished after breakfast compared with dinner (P < .001). Low-calorie breakfast increased feelings of hunger (P < .001), specifically appetite for sweets (P = .007), in the course of the day. Conclusions DIT is clearly higher in the morning than in the evening, irrespective of the consumed calorie amount; that is, this physiological rhythmicity is preserved during hypocaloric nutrition. Extensive breakfasting should therefore be preferred over large dinner meals to prevent obesity and high blood glucose peaks even under conditions of a hypocaloric diet.

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Transcranial direct current stimulation (tDCS) is a neuromodulatory method that has been tested experimentally and has already been used as an adjuvant therapeutic option to treat a number of neurological disorders and neuropsychiatric diseases. Beyond its well known local effects within the brain, tDCS also transiently promotes systemic glucose uptake and reduces the activity of the neurohormonal stress axes. We aimed to test whether the effects of a single tDCS application could be replicated upon double stimulation to persistently improve systemic glucose tolerance and stress axes activity in humans. In a single‐blinded cross‐over study, we examined 15 healthy male volunteers. Anodal tDCS vs sham was applied twice in series. Systemic glucose tolerance was investigated by the standard hyperinsulinaemic‐euglycaemic glucose clamp procedure, and parameters of neurohormonal stress axes activity were measured. Because tDCS‐induced brain energy consumption has been shown to be part of the mechanism underlying the assumed effects, we monitored the cerebral high‐energy phosphates ATP and phosphocreatine by 31phosphorus magnetic resonance spectroscopy. As hypothesised, analyses revealed that double anodal tDCS persistently increases glucose tolerance compared to sham. Moreover, we observed a significant rise in cerebral high‐energy phosphate content upon double tDCS. Accordingly, the activity of the neurohormonal stress axes was reduced upon tDCS compared to sham. Our data demonstrate that double tDCS promotes systemic glucose uptake and reduces stress axes activity in healthy humans. These effects suggest that repetitive tDCS may be a future non‐pharmacological option for combating glucose intolerance in type 2 diabetes patients.