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/m(2)), 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.

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.

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.

Protein v. carbohydrate intake differentially affects liking- and wanting-related brain signalling.

Extreme macronutrient intakes possibly lead to different brain signalling. The aim of the present study was to determine the effects of ingesting high-protein v. high-carbohydrate food on liking and wanting task-related brain signalling (TRS) and subsequent macronutrient intake. A total of thirty female subjects (21.6 (SD 2.2) years, BMI 25.0 (SD 3.7) kg/m²) completed four functional MRI scans: two fasted and two satiated on two different days. During the scans, subjects rated all food items for liking and wanting, thereby choosing the subsequent meal. The results show that high-protein (PROT) v. high-carbohydrate (CARB) conditions were generated using protein or carbohydrate drinks at the first meal. Energy intake and hunger were recorded. PROT (protein: 53.7 (SD 2.1) percentage of energy (En%); carbohydrate: 6.4 (SD 1.3) En%) and CARB conditions (protein: 11.8 (SD 0.6) En%; carbohydrate: 70.0 (SD 2.4) En%) were achieved during the first meal, while the second meals were not different between the conditions. Hunger, energy intake, and behavioural liking and wanting ratings were decreased after the first meal (P< 0.001). Comparing the first with the second meal, the macronutrient content changed: carbohydrate -26.9 En% in the CARB condition, protein -37.8 En% in the PROT condition. After the first meal in the CARB condition, wanting TRS was increased in the hypothalamus. After the first meal in the PROT condition, liking TRS was decreased in the putamen (P< 0.05). The change in energy intake from the first to the second meal was inversely related to the change in liking TRS in the striatum and hypothalamus in the CARB condition and positively related in the PROT condition (P< 0.05). In conclusion, wanting and liking TRS were affected differentially with a change in carbohydrate or protein intake, underscoring subsequent energy intake and shift in macronutrient composition.

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.

Dietary protein - its role in satiety, energetics, weight loss and health.

Obesity is a serious health problem because of its co-morbidities. The solution, implying weight loss and long-term weight maintenance, is conditional on: (i) sustained satiety despite negative energy balance, (ii) sustained basal energy expenditure despite BW loss due to (iii) a sparing of fat-free mass (FFM), being the main determinant of basal energy expenditure. Dietary protein has been shown to assist with meeting these conditions, since amino acids act on the relevant metabolic targets. This review deals with the effects of different protein diets during BW loss and BW maintenance thereafter. Potential risks of a high protein diet are dealt with. The required daily intake is 0·8-1·2 g/kg BW, implying sustaining the original absolute protein intake and carbohydrate and fat restriction during an energy-restricted diet. The intake of 1·2 g/kg BW is beneficial to body composition and improves blood pressure. A too low absolute protein content of the diet contributes to the risk of BW regain. The success of the so-called 'low carb' diet that is usually high in protein can be attributed to the relatively high-protein content per se and not to the relatively lower carbohydrate content. Metabolic syndrome parameters restore, mainly due to BW loss. With the indicated dosage, no kidney problems have been shown in healthy individuals. In conclusion, dietary protein contributes to the treatment of obesity and the metabolic syndrome, by acting on the relevant metabolic targets of satiety and energy expenditure in negative energy balance, thereby preventing a weight cycling effect.

Relatively high-protein or 'low-carb' energy-restricted diets for body weight loss and body weight maintenance?

BACKGROUND: 'Low-carb' diets have been suggested to be effective in body weight (BW) management. However, these diets are relatively high in protein as well. OBJECTIVE: To unravel whether body-weight loss and weight-maintenance depends on the high-protein or the 'low-carb' component of the diet. DESIGN: Body-weight (BW), fat mass (FM), blood- and urine-parameters of 132 participants (age=50 ± 12 yr; BW=107 ± 20 kg; BMI=37 ± 6 kg/m(2); FM=47.5 ± 11.9 kg) were compared after 3 and 12 months between four energy-restricted diets with 33% of energy requirement for the first 3 months, and 67% for the last 9 months: normal-protein normal-carbohydrate (NPNC), normal-protein low-carbohydrate (NPLC); high-protein normal-carbohydrate (HPNC), high-protein low-carbohydrate (HPLC); 24h N-analyses confirmed daily protein intakes for the normal-protein diets of 0.7 ± 0.1 and for the high-protein diets of 1.1 ± 0.2g/kg BW (p<0.01). RESULTS: BW and FM decreased over 3 months (p<0.001): HP (-14.1 ± 4 kg; -11.9 ± 1.7 kg) vs. NP (-11.5 ± 4 kg; -9.3 ± 0.7 kg) (p<0.001); LC (-13.5 ± 4 kg; -11.0 ± 1.2 kg) vs. NC (-12.3 ± 3 kg; -10.3 ± 1.1 kg) (ns). Diet × time interaction showed HPLC (-14.7 ± 5 kg; -11.9 ± 1.6 kg) vs. HPNC (-13.8 ± 3 kg; -11.9 ± 1.8 kg) (ns); NPLC (-12.2 ± 4 kg; -10.0 ± 0.8 kg) vs. NPNC (-10.7 ± 4 kg; -8.6 ± 0.7 kg) (ns); HPLC vs. NPLC (p<0.001); HPNC vs. NPNC (p<0.001). Decreases over 12 months (p<0.001) showed HP (-12.8 ± 4 kg; -9.1 ± 0.8 kg) vs. NP (-8.9 ± 3 kg; -7.7 ± 0.6 kg) (p<0.001); LC (-10.6 ± 4 kg; -8.3 ± 0.7 kg) vs. NC (11.1 ± 3 kg; 9.3 ± 0.7 kg) (ns). Diet × time interaction showed HPLC (-11.6 ± 5 kg ; -8.2 ± 0.7 kg) vs. HPNC (-14.1 ± 4 kg; -10.0 ± 0.9 kg) (ns); NPNC (-8.2 ± 3 kg; -6.7 ± 0.6 kg) vs. NPLC (-9.7 ± 3 kg; -8.5 ± 0.7 kg) (ns); HPLC vs. NPLC (p<0.01); HPNC vs. NPNC (p<0.01). HPNC vs. all other diets reduced diastolic blood pressure more. Relationships between changes in BW, FM, FFM or metabolic parameters and energy percentage of fat in the diet were not statistically significant. Metabolic profile and fat-free-mass were improved following weight-loss. CONCLUSION: Body-weight loss and weight-maintenance depends on the high-protein, but not on the 'low-carb' component of the diet, while it is unrelated to the concomitant fat-content of the diet.

Satiating capacity and post-prandial relationships between appetite parameters and gut-peptide concentrations with solid and liquefied carbohydrate.

BACKGROUND: Differences in satiating capacity of liquid and solid meals are unclear. OBJECTIVE: Investigating appetite parameters, physiological measurements and within-subject relationships after consumption of a single macronutrient, subject-specific carbohydrate meal in liquefied versus solid form, controlled for energy density, weight and volume. DESIGN: In a cross-over design, ten male subjects (age = 21.1±3.9 y, BMI = 22.4±1.2 kg/m(2)) consumed a solid (CS, whole peaches +750 ml water) and liquefied carbohydrate (CL, peach blended in 500 ml water +250 ml water) lunch. Appetite profiles, insulin-, glucose- and ghrelin concentrations were measured over three hours. Post-prandial relationships between appetite and blood parameters were calculated using subject-specific regression analyses. RESULTS: Fullness ratings were higher in the CL (85±5 mm) compared to the CS condition (73±8 mm) at 20 min (p<0.03). Glucose concentrations peaked 20 to 30 min after the start of the lunch in the CL condition, and 30 to 40 min after start of the CS condition. Correspondingly, insulin concentrations were peaked at 20-30 min in the CL condition, and at 30-40 min in the CS condition. AUC or condition x time interactions were not different comparing the CL and the CS condition. Insulin was significantly higher in the CS compared to the CL condition 40 min after the start of the lunch (p<0.05). Fullness scores were significantly related to insulin concentrations but not to glucose concentrations; desire to eat scores were significantly associated with ghrelin concentrations in both, the CL and the CS condition. The relationship between fullness scores and glucose concentrations was not statistically significant. CONCLUSION: Liquefied and solid carbohydrate meals do not differ in satiating capacity, supported by appetite profile and relevant blood parameters. Postprandially, fullness and desire to eat were associated with respectively insulin and ghrelin concentrations.

Sex differences in HPA axis activity in response to a meal.

BACKGROUND: Sex may influence the relationship between HPA axis functioning and obesity. This has been suggested to be due to sex-specific differences in body composition, body fat distribution and psychological variables. Age and the use of oral contraceptives may also influence the relationship between HPA axis functioning and obesity. OBJECTIVE: To systematically investigate whether body composition, body fat distribution, psychological variables, age, or possible oral contraceptive use contribute to sex differences in HPA axis activity in response to a meal. METHODS: Subjects were men (n=19) and women (n=19) between 18 and 51 years old with BMI between 20.3 and 33.2 kg/m(2). HPA axis activity was measured by salivary free cortisol levels before consuming a meal, and at 45, 75 and 125 min postprandial on four repeated test days. Anthropometric and body composition measurements were performed. Questionnaires were used to assess cognitive eating behavior and trait anxiety level. RESULTS: No differences between the test days in postprandial cortisol responses appeared. Responses were significantly higher in men compared with women (p<.05). No significant correlations were found between cortisol concentrations and sex-specific body composition or body fat distribution. Psychological variables did not contribute to differences in cortisol responses after a meal between men and women. In women, baseline cortisol concentrations correlated inversely with age (p=.024). CONCLUSION: Higher HPA axis activity following a meal in men vs. women remained irrespective of sex-specific differences in body composition, body fat distribution, psychological variables, or in age. In women baseline cortisol concentrations were age-dependent.

High HPA-axis activation disrupts the link between liking and wanting with liking and wanting related brain signaling.

BACKGROUND: Eating behavior changes under stress, i.e. during high HPA-axis activation. AIM: Assessment of effects of high versus low HPA-axis activation on liking and wanting related brain signaling in relevant regions. METHODS: 15 female subjects (21.5±0.4 years, BMI=22.2±0.4) completed fMRI scans on 2 days, in a fasted as well as a satiated condition on each day. The days were sorted by HPA-axis activation, resulting in two sufficiently separated HPA-axis states which were statistically confirmed (p<.05). During scans, subjects rated liking and wanting for food images; wanting indicated food choice for the subsequent meal. Energy-intake, hunger and fullness were additionally recorded. RESULTS: Hunger changed significantly over the meal (p<.001). Energy intake was lower during the second meal (p<.001). Behavioral wanting was lower after breakfast (p<.01), behavioral liking did not change. During low HPA-activation, liking task related signaling (TRS) pre-meal in the anterior insula predicted behavioral liking, wanting TRS in the anterior insula, nucleus accumbens and thalamus predicted behavioral wanting. During high HPA-activation, these relationships were not present pre-meal, but post-meal behavioral liking was predicted in the nucleus accumbens and wanting in the caudate. CONCLUSION: High HPA-axis activation disrupted and redirected the connection of behavioral liking/wanting with the specifically associated brain signaling in relevant regions.

Lack of effect of high-protein vs. high-carbohydrate meal intake on stress-related mood and eating behavior.

BACKGROUND: Consumption of meals with different macronutrients, especially high in carbohydrates, may influence stress-related eating behavior. We aimed to investigate whether consumption of high-protein vs. high-carbohydrate meals influences stress-related mood, food reward, i.e. 'liking' and 'wanting', and post-meal energy intake. METHODS: Participants (n = 38, 19m/19f, age = 25 ± 9 y, BMI = 25.0 ± 3.3 kg/m2) came to the university four times, fasted, once for a stress session receiving a high-protein meal, once for a rest session receiving a high-protein meal, once for a stress session receiving a high-carbohydrate meal and once for a rest session receiving a high-carbohydrate meal (randomized cross-over design). The high-protein and high-carbohydrate test meals (energy percentage protein/carbohydrate/fat 65/5/30 vs. 6/64/30) matched for energy density (4 kJ/g) and daily energy requirements (30%). Stress was induced using an ego-threatening test. Pre- and post-meal 'liking' and 'wanting' (for bread, filling, drinks, dessert, snacks, stationery (non-food alternative as control)) was measured by means of a computer test. Following the post-meal 'wanting' measurement, participants received and consumed their wanted food items (post-meal energy intake). Appetite profile (visual analogue scales), mood state (Profile Of Mood State and State Trait Anxiety Inventory questionnaires), and post-meal energy intake were measured. RESULTS: Participants showed increased feelings of depression and anxiety during stress (P < 0.01). Consumption of the test meal decreased hunger, increased satiety, decreased 'liking' of bread and filling, and increased 'liking' of placebo and drinks (P < 0.0001). Food 'wanting' decreased pre- to post-meal (P < 0.0001). The high-protein vs. high-carbohydrate test meal induced lower subsequent 'wanting' and energy intake (1.7 ± 0.3 MJ vs. 2.5 ± 0.4 MJ) only in individuals characterized by disinhibited eating behavior (factor 2 Three Factor Eating Questionnaire, n = 16), during rest (P ≤ 0.01). This reduction in 'wanting' and energy intake following the high-protein meal disappeared during stress. CONCLUSIONS: Consumption of a high-protein vs. high-carbohydrate meal appears to have limited impact on stress-related eating behavior. Only participants with high disinhibition showed decreased subsequent 'wanting' and energy intake during rest; this effect disappeared under stress. Acute stress overruled effects of consumption of high-protein foods. TRIAL REGISTRATION: The study was registered in the Dutch Trial Register (NTR1904). The protocol described here in this study deviates from the trial protocol approved by the Medical Ethical Committee of the Maastricht University as it comprises only a part of the approved trial protocol.

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.

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.

Associations between anthropometrical measurements, body composition, single-nucleotide polymorphisms of the hypothalamus/pituitary/adrenal (HPA) axis and HPA axis functioning.

BACKGROUND: The relationship between hypothalamus/pituitary/adrenal (HPA) axis functioning and (visceral) obesity may be explained by single-nucleotide polymorphisms (SNPs) of the HPA axis. Objective To investigate the relationship between the HPA axis SNP's 'BclI' in the glucocorticoid receptor gene and C8246T in the POMC gene and anthropometric measurements, body composition, 5-h cortisol concentrations, HPA axis feedback sensitivity, as well as HPA axis feedback sensitivity under stress in men and women. DESIGN/SUBJECTS/MEASUREMENTS: We assessed in 92 men and 102 women (18-55 years, BMI 19-41 kg/m(2) ) anthropometry, body composition using hydrodensitometry and deuterium dilution method, cortisol variability by measuring 5-h cortisol concentrations, HPA axis feedback functioning using a dexamethasone suppression test and HPA axis functioning under a challenged condition consisting of a standardized high intensity test with ingestion of 4 mg dexamethasone. RESULTS: In female participants, the 8246C allele carriers compared to the 8246T allele carries were associated with a higher 5-h cortisol exposure (1·52 × 10(5) ± 0·8 vs 1·18 × 10(5) ± 0·6 nm·min, P < 0·05) and higher baseline postdexamethasone cortisol concentrations (54·5 ± 35·6 vs 37·4 ± 18·5 nm, P < 0·05). In male participants regarding the C8246T allele carriers and in both male and female participants regarding the BclI genotypes, no significant differences in anthropometric measurements, body composition and HPA axis functioning were observed. Multiple regression analysis showed that only increased 5-h cortisol exposure significantly related to changes in anthropometric measurements and body composition; the BclI and C8246T genotypes were not associated. CONCLUSION: Our preliminary data show that in both men and women (18-55 years, BMI 19-41 kg/m(2) ), the SNP's BclI and C8246T of the HPA axis were primarily related to altered HPA axis functioning, rather than to altered anthropometric measurements and body composition.

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, 19 m/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 mm VAS) 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.

Staggered meal consumption facilitates appetite control without affecting postprandial energy intake.

Meal pattern may influence hormone and appetite dynamics and food intake. The objective of the study was to determine the effects of staggered compared with nonstaggered meal consumption on hormone and appetite dynamics, food reward (i.e. "liking," "wanting"), and subsequent energy intake. The study was conducted in a randomized cross-over design. Participants (n = 38, age = 24 ± 6 y, BMI = 25.0 ± 3.1 kg/m(2)) came to the university twice for consumption of a 4-course lunch (40% of the daily energy requirements) in 0.5 h (nonstaggered) or in 2 h with 3 within-meal pauses (staggered) followed by ad libitum food intake. Throughout the test sessions, glucagon-like peptide (GLP)-1, peptide tyrosine-tyrosine (PYY(3-36)), ghrelin, appetite, and food reward were measured. In the staggered compared with nonstaggered meal condition, peak values of GLP-1, PYY(3-36), and satiety were lower and time to peak values were higher (P < 0.02); the nadir value of hunger was higher, and time to nadir values of ghrelin and hunger were higher (P < 0.0001). Prior to ad libitum food intake, GLP-1 concentrations and satiety ratings were greater, ghrelin concentrations and hunger ratings were smaller, and food "wanting" was less in the staggered compared with nonstaggered meal condition (P < 0.05). However, this did not affect ad libitum energy intake (1.7 ± 0.3 vs. 1.9 ± 0.2 MJ). In conclusion, staggered compared with nonstaggered meal consumption induces less pronounced hormone and appetite dynamics. Moreover, it results in higher final GLP-1 concentrations and satiety ratings, lower ghrelin concentrations and hunger ratings, and lower food "wanting" prior to ad libitum food intake. However, this was not translated into lower energy intake.

Stress augments food 'wanting' and energy intake in visceral overweight subjects in the absence of hunger.

Stress may induce eating in the absence of hunger, possibly involving changes in food reward, i.e. 'liking' and 'wanting'. The objective of this study was to assess the effects of acute psychological stress on food reward, and on energy intake, in visceral overweight (VO) vs. normal weight (NW) subjects. Subjects (27 NW, age=26 ± 9 yrs, BMI=22 ± 2 kg/m²; 15 VO, age=36 ± 12 yrs, BMI=28 ± 1 kg/m²) came to the university twice, fasted, for either a rest or stress condition (randomized cross-over design). Per test-session 'liking' and 'wanting' for 72 items divided in six categories (bread, filling, drinks, dessert, snacks, and stationery (control)) were measured twice, each time followed by a wanted meal. Appetite profile (visual analogue scales, VAS), heart rate, mood state and level of anxiety (POMS/STAI questionnaires) were measured. High hunger and low satiety (64 ± 19, 22 ± 20 mmVAS) confirmed the fasted state. Elevated heart rate, anger and confusion scores (p ≤ 0.03) confirmed the stress vs. rest condition. Consumption of the first meal decreased hunger, increased satiety, and decreased ranking of 'liking' of bread vs. increased ranking of 'liking' of the control (p<0.001). 'Wanting' for dessert and snacks, energy intake, carbohydrate and fat intake for the second meal stress vs. rest relatively increased in VO vs. decreased in NW (p<0.02). During stress vs. rest VO showed a 6 ± 9% increase in percentage of daily energy requirements consumed over the two meals (p=0.01). To conclude, visceral overweight subjects showed stress-induced food intake in the absence of hunger, resulting in an increased energy intake.

A solid high-protein meal evokes stronger hunger suppression than a liquefied high-protein meal.

Hunger is a potential problem for compliance with an energy-restricted diet. Relatively high-protein meal-replacement products have been shown to diminish this problem; they are available as liquid and solid meals, yet their physical state can affect hunger suppression. The objective was to investigate the differences in appetite profile and physiological parameters after consumption of a single-macronutrient, subject-specific, high-protein meal in liquefied vs. solid form, controlled for energy density, weight, and volume. Ten male subjects (age: 21.1 ± 3.9 years; BMI: 22.4 ± 1.2 kg/m²) were offered lunch subject-specifically as 15% of daily energy requirement (DER), consisting of solid (steamed chicken breast + 750 ml water) or liquefied protein (steamed chicken breast blended in 500 ml water + 250 ml water). Appetite profiles, insulin, glucose, and ghrelin were measured over 3 h. Comparing the solid vs. liquefied condition, oral exposure time did not differ between conditions (19.2 ± 0.4 and 18.8 ± 0.6 min, respectively; P = 0.13). Area under the curve (AUC) effects were observed for thirst; statistically significant condition × time interactions and statistically significant differences at several time points were observed for desire to eat (condition × time P < 0.05; 31 ± 6 mm vs. 53 ± 8 mm; P < 0.04 at 115 min) and thirst (condition × time P < 0.01; 27 ± 8 mm vs. 41 ± 8 mm; P < 0.05 at 30 min and 23 ± 6 mm vs. 41 ± 8 mm; P < 0.02 at 70 min) to be lower, while hunger suppression (79 ± 3 mm and 52 ± 10 mm; P < 0.03 at 20 min and 61 ± 7 mm and 44 ± 8 mm; P < 0.03 at 115 min) was higher in the solid condition. Glucose, insulin, and ghrelin concentration curves were similar for both conditions. In conclusion, solid protein evokes a stronger suppression of hunger and desire to eat than liquefied protein.

Effects of single macronutrients on serum cortisol concentrations in normal weight men.

A previous study reported that a high carbohydrate meal, in contrast to a high protein/fat meal, significantly increased cortisol concentrations in visceral obese subjects. The objective of this study was to identify effects of single macronutrients on plasma cortisol concentrations. Ten male subjects (age 27.3±7.4y, BMI 22.1±1.7kg/m(2)) were studied in a randomized crossover design on four days around lunchtime after consuming breakfast matched for daily energy requirements (DER 20%). For lunch they consumed one liter of a shake (DER 18%) containing either fat, protein or carbohydrate, with a raspberry taste and similar hedonic value (59±2mm on a 100mm VAS), using water as control. Serum cortisol concentrations were measured before lunch and during three hours following lunch. Baseline cortisol concentrations did not differ among treatments. The protein as well as the fat lunch caused a significant decrease in cortisol concentrations when compared to the carbohydrate lunch, and showed no difference from the control condition (p<0.05). The cortisol response in the protein condition (AUC=37,024±3518nmol/L min) and in the fat condition (AUC=35,977±3562nmol/L min) were significantly smaller when compared with the cortisol response in the carbohydrate condition (AUC=47,310±3667nmol/L min) (p<0.03), but did not differ from the control condition (AUC=32,784±1683nmol/L min) (Fig. 1). The cortisol response in the carbohydrate condition was significantly higher when compared with the response in the control condition (p<0.004). We conclude that cortisol concentrations decreased after protein or fat intake, which was not different from control; this decrease was prevented by carbohydrate intake.

Genetic associations with acute stress-related changes in eating in the absence of hunger.

BACKGROUND: Acute psychological stress is associated with eating in the absence of hunger. OBJECTIVE: To investigate if BclI and FTO polymorphisms are associated with eating in the absence of hunger as a result of acute psychological stress. METHODS: FTO (rs9939609) and BclI were genotyped in 98 subjects (BMI=23.9+/-3.3kg/m(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 STAI (State Trait Anxiety Index) state scores. RESULTS: In comparison with the FTO T allele, the A allele was associated with an increased feelings of hunger after food intake in the stress (11+/-10 vs. 18+/-15, p<0.01) and control condition (12+/-9 vs. 16+/-12, p<0.05), even though food intake was not different. For the first time, it was observed that in comparison to the BclI C/C genotype, the BclI G/G genotype was associated with higher STAI states scores at 0, 10, and 20min after the stress condition (30.8+/-6.4 vs. 36.3+/-8.2; 28.3+/-5.5 vs. 32.3+/-7.5; 27.7+/-6.1 vs. 31.2+/-7.5, p<0.05). Additionally, the BclI G/G genotype was associated with a larger difference in energy intake between the stress and control condition, in comparison with the BclI C/C genotype (136.6+/-220.4 vs. 29.4+/-176.3kJ, p<0.04). CONCLUSION: In concordance with previous studies, the FTO A allele is related to a lower feeling of hunger after a standardized meal. For the first time, the BclI G/G genotype is shown to be associated with increased sensitivity to psychological stress, and increased eating in the absence of hunger after stress. PRACTICE IMPLICATIONS: Interventions to reduce body weight should consider the subjects' genetic background.