Sofie G.T. Lemmens

Acute Stress-related Changes in Eating in the Absence of Hunger

Obesity results from chronic deregulation of energy balance, which may in part be caused by stress. Our objective was to investigate the effect of acute and psychological stress on food intake, using the eating in the absence of hunger paradigm, in normal and overweight men and women (while taking dietary restraint and disinhibition into account). In 129 subjects (BMI = 24.5 ± 3.4 kg/m2 and age = 27.6 ± 8.8 years), scores were determined on the Three Factor Eating Questionnaire (dietary restraint = 7.2 ± 4.4; disinhibition = 4.5 ± 2.6; feeling of hunger = 3.9 ± 2.6) and State‐Trait Anxiety Inventory (trait score = 31.7 ± 24.2). In a randomized crossover design, the “eating in absence of hunger” protocol was measured as a function of acute stress vs. a control task and of state anxiety scores. Energy intake from sweet foods (708.1 kJ vs. 599.4 kJ, P < 0.03) and total energy intake (965.2 kJ vs. 793.8 kJ, P < 0.01) were significantly higher in the stress condition compared to the control condition. Differences in energy intake between the stress and control condition were a function of increase in state anxiety scores during the stress task (Δ state anxiety scores) (R2 = 0.05, P < 0.01). This positive relationship was stronger in subjects with high disinhibition scores (R2 = 0.12, P < 0.05). Differences in state anxiety scores were a function of trait anxiety scores (R2 = 0.07, P < 0.05). We conclude that acute psychological stress is associated with eating in the absence of hunger, especially in vulnerable individuals characterized by disinhibited eating behavior and sensitivity to chronic stress.

Acute stress and food-related reward activation in the brain during food choice during eating in the absence of hunger.

Background:Stress results in eating in the absence of hunger, possibly related to food reward perception.Hypothesis:Stress decreases food reward perception.Aim:Determine the effect of acute stress on food choice and food choice reward-related brain activity.Subjects:Nine females (BMI=21.5±2.2 kg/m2, age=24.3±3.5 years).Procedure:Fasted subjects came twice to randomly complete either a rest or stress condition. Per session, two functional MRI scans were made, wherein the subjects chose the subsequent meal (food images). The rewarding value of the food was measured as liking and wanting. Food characteristics (for example, crispiness, fullness of taste and so on), energy intake, amount of each macronutrient chosen, plasma cortisol and Visual Analog Scale (VAS) hunger and satiety were measured.Results:Fasted state was confirmed by high hunger (80±5 mm VAS). Breakfast energy intake (3±1 MJ) and liking were similar in all conditions. Wanting was lower postprandially (Δ=−0.3 items/category, P<0.01). Breakfast decreased hunger (−42 mm VAS, P<0.01). Postprandially, energy intake (−1.1 MJ), protein intake (−14.7 g) and carbohydrate intake (−32.7 g all P<0.05) were lower. Fat intake was not different (−7.3, P=0.4). Putamen activity was not lower postprandially. Cortisol levels were increased in the stress condition (Area under the curve of cortisol: ΔAUC=+2.2 × 104 nmol min−1 l−1, P<0.05). Satiety was lower after breakfast (−8 mm VAS, P<0.01). Postprandial energy intake, protein intake and carbohydrate intake were relatively higher compared with the rest condition, resulting from more choice for crispiness and fullness of taste (P<0.05). Brain activation was reduced in reward areas: amygdala, hippocampus and cingulate cortex (AUC=−13.33, −1.34, −2.56% blood oxygen level dependent (BOLD) s for choosing breakfast and AUC=−9.31, −1.25, −2.34%BOLD s<0.05 for choosing the second meal). Putamen activation was decreased postprandially (AUC=−1.2%BOLD s, P<0.05).Conclusion:Reward signaling and reward sensitivity were significantly lower under stress, coinciding with increased energy intake from food choice for more crispiness and fullness of taste. The changes in putamen activation may reflect specifically decreased reward prediction sensitivity.

Normal Protein Intake Is Required for Body Weight Loss and Weight Maintenance, and Elevated Protein Intake for Additional Preservation of Resting Energy Expenditure and Fat Free Mass

Energy-restricted high-protein diets (HPDs) have shown favorable results for body weight (BW) management, yet studies differ in their outcomes depending on the dietary protein content. Our objective was to determine the effects of dietary protein content on BW loss-related variables during a 6-mo energy restriction with the use of diets containing protein at the level of requirement [normal-protein diet (NPD), 0.8 g · kg BW(-1) (.) d(-1)] and above (HPD, 1.2 g · kg BW(-1) (.) d(-1)). In overweight and obese participants (24 men and 48 women), BW, body composition, and metabolic responses were assessed before and after subsequent energy intakes of 100, 33, and 67% of the original individual daily energy requirements. Protein intake was consistent in the NPD (0.8 ± 0.3 g · kg BW(-1) (.) d(-1)) and HPD (1.2 ± 0.3 g · kg BW(-1) (.) d(-1)) groups throughout the study (P < 0.001). BMI and body fat mass similarly decreased in the NPD and HPD groups (P < 0.01). Fat free mass (FFM), resting energy expenditure (REE) compared with predicted REE, and diastolic blood pressure (DBP) changed favorably with the HPD compared with the NPD group after BW loss (P < 0.05). A NPD of 0.8 g · kg BW(-1) (.) d(-1) is sufficient for BW management, whereas a HPD of 1.2 g · kg BW(-1) (.) d(-1) is necessary for preservation of REE and a stronger initial sparing effect of FFM and lowering of DBP.

Is social jetlag associated with an adverse endocrine, behavioral, and cardiovascular risk profile?

Social jetlag represents the discrepancy between circadian and social clocks, which is measured as the difference in hours in midpoint of sleep between work days and free days. Previous studies have shown social jetlag to be associated with body mass index (BMI), glycated hemoglobin levels, heart rate, depressive symptoms, smoking, mental distress and alcohol use. The objective of our current study was to investigate, in a group of 145 apparently healthy participants (67 men and 78 women, aged 18-55 years, BMI 18-35 kg/m2), the prevalence of social jetlag and its association with adverse endocrine, behavioral and cardiovascular risk profiles as measured in vivo. participants with ≥2 h social jetlag had higher 5-h cortisol levels, slept less during the week, were more often physically inactive and had an increased resting heart rate, compared with participants who had ≤1 h social jetlag. We therefore concluded that social jetlag is associated with an adverse endocrine, behavioral and cardiovascular risk profile in apparently healthy participants. These adverse profiles put healthy participants at risk for development of metabolic diseases and mental disorders, including diabetes and depression, in the near future.

Differences between liking and wanting signals in the human brain and relations with cognitive dietary restraint and body mass index

BACKGROUND Eating behavior is determined, to a significant extent, by the rewarding value of food (ie, liking and wanting). OBJECTIVE We determined brain regions involved in liking and wanting and related brain signaling to body mass index (BMI; in kg/m(2)) and dietary restraint. DESIGN Fifteen normal-weight female subjects [mean ± SEM age: 21.5 ± 0.4 y; BMI: 22.2 ± 0.2] completed a food-choice paradigm by using visually displayed food items during functional magnetic resonance imaging scans. Two scans were made as follows: one scan was made in a fasted condition, and one scan was made in a satiated condition. The paradigm discriminated between liking and wanting, and subjects were offered items rated highly for wanting immediately after each scan. Imaging contrasts for high and low liking and wanting were made, and data for regions of interest were extracted. Activation related to liking and wanting, respectively, was determined. Outcomes were correlated to cognitive dietary restraint and BMI. RESULTS Dietary restraint predicted liking task-related signaling (TRS) in the amygdala, striatum, thalamus, and cingulate cortex (r = -0.5 ± 0.03, P < 0.00001). In the nucleus accumbens, the premeal liking and wanting TRS and premeal to postmeal liking TRS changes correlated positively with dietary restraint [bilateral average r = 0.6 ± 0.02, P < 0.04 (Bonferroni corrected)]. BMI and hunger predicted wanting TRS in the hypothalamus and striatum (P < 0.05). Postmeal liking TRS in the striatum, anterior insula, and cingulate cortex and wanting TRS in the striatum predicted the energy intake (liking: r = -0.3 ± 0.05, P < 0.0001; wanting: r = -0.3 ± 0.03, P < 0.00001). CONCLUSIONS Successful dietary restraint was supported by liking TRS from premeal to postmeal in the nucleus accumbens. Reward-related signaling was inversely related to BMI and energy intake, indicating reward deficiency.

Protein leverage affects energy intake of high-protein diets in humans

BACKGROUND The protein leverage hypothesis requires specific evidence that protein intake is regulated more strongly than energy intake. OBJECTIVE The objective was to determine ad libitum energy intake, body weight changes, and appetite profile in response to protein-to-carbohydrate + fat ratio over 12 consecutive days and in relation to age, sex, BMI, and type of protein. DESIGN A 12-d randomized crossover study was performed in 40 men and 39 women [mean ± SD age: 34.0 ± 17.6 y; BMI (in kg/m(2)): 23.7 ± 3.4] with the use of diets containing 5%, 15%, and 30% of energy from protein from a milk or plant source. RESULTS Protein-content effects did not differ by age, sex, BMI, or type of protein. Total energy intake was significantly lower in the high-protein (7.21 ± 3.08 MJ/d) condition than in the low-protein (9.33 ± 3.52 MJ/d) and normal-protein (9.62 ± 3.51 MJ/d) conditions (P = 0.001), which was predominantly the result of a lower energy intake from meals (P = 0.001). Protein intake varied directly according to the amount of protein in the diet (P = 0.001). The AUC of visual analog scale appetite ratings did not differ significantly, yet fluctuations in hunger (P = 0.019) and desire to eat (P = 0.026) over the day were attenuated in the high-protein condition compared with the normal-protein condition. CONCLUSIONS We found evidence to support the protein leverage hypothesis in that individuals underate relative to energy balance from diets containing a higher protein-to-carbohydrate + fat ratio. No evidence for protein leverage effects from diets containing a lower ratio of protein to carbohydrate + fat was obtained. It remains to be shown whether a relatively low protein intake would cause overeating or would be the effect of overeating of carbohydrate and fat. The study was registered at clinicaltrials.gov as NCT01320189.

Changes in gut hormone and glucose concentrations in relation to hunger and fullness

BACKGROUND The search for biomarkers of appetite is very active. OBJECTIVES The aims were to compare dynamics of hunger and fullness ratings on a visual analog scale (VAS) with dynamics of glucagon-like peptide 1, peptide tyrosine-tyrosine, ghrelin, glucose, and insulin concentrations throughout different meal patterns-and thus different timings of nutrient delivery to the gut-by using a statistical approach that focuses on within-subject relations of these observations and to investigate whether appetite ratings are synchronized with or lag behind or in front of changes in hormone and glucose concentrations. DESIGN Subjects (n = 38) with a mean (±SD) age of 24 ± 6 y and BMI (in kg/m(2)) of 25.1 ± 3.1 came to the university twice for consumption of a 4-course lunch in 0.5 or 2 h (randomized crossover design). Per subject regression slopes and R(2) values of VAS scores on hormone and glucose concentrations were calculated. We tested whether the means of the slopes were different from zero. Regarding possible lags in the relations, the analyses were repeated with VAS scores related to hormone and glucose concentrations of the relevant previous and following measurement periods. RESULTS VAS scores and hormone and glucose concentrations changed synchronously (P < 0.005, R(2) = 0.4-0.7). Changes in ghrelin concentrations lagged behind (10-30 min) changes in hunger scores (P < 0.005, R(2) = 0.7) and insulin concentrations (P < 0.005, R(2) = 0.6), which suggests a role for insulin as a possible negative regulator of ghrelin. No major differences in slopes and R(2) values were found between the meal patterns. CONCLUSIONS This method may be useful for understanding possible differences in relations between VAS scores and hormone and glucose concentrations between subjects or conditions. Yet, the reported explained variation of 40% to 70% seems to be too small to use hormone and glucose concentrations as appropriate biomarkers for appetite, at least at the individual level and probably at the group level. This study started in 2007, which means that it was not registered as a clinical trial.

Increased sensitivity to food cues in the fasted state and decreased inhibitory control in the satiated state in the overweight

BACKGROUND Flexibility of food reward-related brain signaling (FRS) between food and nonfood stimuli may differ between overweight and normal-weight subjects and depend on a fasted or satiated state. OBJECTIVE The objective was to assess this flexibility in response to visual food and nonfood cues. DESIGN Twenty normal-weight [mean ± SEM BMI (in kg/m(2)) = 22.7 ± 0.2; mean ± SEM age = 22.4 ± 0.4 y] and 20 overweight (BMI = 28.1 ± 0.3; age = 24.0 ± 0.7 y) participants completed 2 fMRI scans. Subjects arrived in a fasted state and consumed a breakfast consisting of 20% of subject-specific energy requirements between 2 successive scans. A block paradigm and a food > nonfood contrast was used to determine FRS. RESULTS An overall stimulus × condition × subject group effect was observed in the anterior cingulate cortex (ACC) (P < 0.006, F((1,38)) = 9.12) and right putamen (P < 0.006, F((1,38)) = 9.27). In all participants, FRS decreased from the fasted to the satiated state in the cingulate (P < 0.005, t((39)) = 3.15) and right prefrontal cortex (PFC) (P < 0.006, t((39)) = 3.00). In the fasted state, they showed FRS in the PFC (P < 0.004, t((39)) = 3.17), left insula (P < 0.009, t((39)) = 2.95), right insula (P < 0.005, t((39)) = 3.12), cingulate cortex (P < 0.004, t((39)) = 3.21), and thalamus (P < 0.006, t((39)) = 2.96). In the satiated state, FRS was limited to the left insula (P < 0.005, t((39)) = 3.21), right insula (P < 0.006, t((39)) = 3.04), and cingulate cortex (P < 0.005, t((39)) = 3.15). Regarding subject group, in the fasted state, FRS in the ACC was more pronounced in overweight than in normal-weight subjects (P < 0.005, F((1,38)) = 9.71), whereas in the satiated state, FRS was less pronounced in overweight than in normal-weight subjects in the ACC (P < 0.006, F((1,38)) = 9.18) and PFC (P < 0.006, F((1,38)) = 8.86), which suggests lower inhibitory control in the overweight. CONCLUSION FRS was higher in the overweight in the satiated state; however, when sufficiently satiated, the overweight showed decreased inhibitory control signalling, which facilitates overeating. This trial was registered in the Dutch clinical trial register as NTR2174.

Influence of Consumption of a High-Protein vs. High-Carbohydrate Meal on the Physiological Cortisol and Psychological Mood Response in Men and Women

Consumption of meals with different macronutrient contents, especially high in carbohydrates, may influence the stress-induced physiological and psychological response. The objective of this study was to investigate effects of consumption of a high-protein vs. high-carbohydrate meal on the physiological cortisol response and psychological mood response. Subjects (n = 38, 19m/19f, age = 25±9 yrs, BMI = 25.0±3.3 kg/m2) came to the university four times, fasted, for either condition: rest-protein, stress-protein, rest-carbohydrate, stress-carbohydrate (randomized cross-over design). Stress was induced by means of a psychological computer-test. The test-meal was either a high-protein meal (En% P/C/F 65/5/30) or a high-carbohydrate meal (En% P/C/F 6/64/30), both meals were matched for energy density (4 kJ/g) and daily energy requirements (30%). Per test-session salivary cortisol levels, appetite profile, mood state and level of anxiety were measured. High hunger, low satiety (81±16, 12±15 mmVAS) confirmed the fasted state. The stress condition was confirmed by increased feelings of depression, tension, anger, anxiety (AUC stress vs. rest p<0.02). Consumption of the high-protein vs. high-carbohydrate meal did not affect feelings of depression, tension, anger, anxiety. Cortisol levels did not differ between the four test-sessions in men and women (AUC nmol·min/L p>0.1). Consumption of the test-meals increased cortisol levels in men in all conditions (p<0.01), and in women in the rest-protein and stress-protein condition (p<0.03). Men showed higher cortisol levels than women (AUC nmol·min/L p<0.0001). Consumption of meals with different macronutrient contents, i.e. high-protein vs. high-carbohydrate, does not influence the physiological and psychological response differentially. Men show a higher meal-induced salivary cortisol response compared with women.

Distinct associations between energy balance and the sleep characteristics slow wave sleep and rapid eye movement sleep.

Context:Epidemiologically, an inverse relationship between body mass index (BMI) and sleep duration is observed. Intra-individual variance in the amount of slow wave sleep (SWS) or rapid eye movement (REM) sleep has been related to variance of metabolic and endocrine parameters, which are risk factors for the disturbance of energy balance (EB).Objective:To investigate inter-individual relationships between EB (EB=∣energy intake–energy expenditure∣, MJ/24 h), SWS or REM sleep, and relevant parameters in normal-weight men during two 48 h stays in the controlled environment of a respiration chamber.Subjects and methods:A total of 16 men (age 23±3.7 years, BMI 23.9±1.9 kg m−2) stayed in the respiration chamber twice for 48 h to assure EB. Electroencephalography was used to monitor sleep (2330–0730 hrs). Hunger and fullness were scored by visual analog scales; mood was determined by State Trait Anxiety Index-state and food reward by liking and wanting. Baseline blood and salivary samples were collected before breakfast. Subjects were fed in EB, except for the last dinner, when energy intake was ad libitum.Results:The subjects slept on average 441.8±49 min per night, and showed high within-subject reliability for the amount of SWS and REM sleep. Linear regression analyses showed that EB was inversely related to the amount of SWS (r=−0.43, P<0.03), and positively related to the amount of REM sleep (r=0.40, P<0.05). Relevant parameters such as hunger, reward, stress and orexigenic hormone concentrations were related to overeating, as well as to the amount of SWS and REM sleep, however, after inclusion of these parameters in a multiple regression, the amount of SWS and REM sleep did not add to the explained variance of EB, which suggests that due to their individual associations, these EB parameters are mediator variables.Conclusion:A positive EB due to overeating, was explained by a smaller amount of SWS and higher amount of REM sleep, mediated by hunger, fullness, State Trait Anxiety Index-state scores, glucose/insulin ratio, and ghrelin and cortisol concentrations.