A resting-state fMRI study of obese females between pre- and postprandial states before and after bariatric surgery.

Past studies utilizing resting-state functional MRI (rsfMRI), have shown that obese humans exhibit altered activity in brain areas related to reward compared to normal-weight controls. However, to what extent bariatric surgery-induced weight loss alters resting-state brain activity in obese humans is less well-studied. Thus, we measured the fractional amplitude of low-frequency fluctuations from eyes-closed, rsfMRI in obese females (n = 11, mean age = 42 years, mean BMI = 41 kg/m2 ) in both a pre- and postprandial state at two time points: four weeks before, and four weeks after bariatric surgery. Several brain areas showed altered resting-state activity following bariatric surgery, including the putamen, insula, cingulate, thalamus and frontal regions. Activity augmented by surgery was also dependent on prandial state. For example, in the fasted state, activity in the middle frontal and pre- and postcentral gyri was found to be decreased after surgery. In the sated state, activity within the insula was increased before, but not after surgery. Collectively, our results suggest that resting-state neural functions are rapidly affected following bariatric surgery and the associated weight loss and change in diet.

An obesity-associated risk allele within the FTO gene affects human brain activity for areas important for emotion, impulse control and reward in response to food images.

Understanding how genetics influences obesity, brain activity and eating behaviour will add important insight for developing strategies for weight-loss treatment, as obesity may stem from different causes and as individual feeding behaviour may depend on genetic differences. To this end, we examined how an obesity risk allele for the FTO gene affects brain activity in response to food images of different caloric content via functional magnetic resonance imaging (fMRI). Thirty participants homozygous for the rs9939609 single nucleotide polymorphism were shown images of low- or high-calorie food while brain activity was measured via fMRI. In a whole-brain analysis, we found that people with the FTO risk allele genotype (AA) had increased activity compared with the non-risk (TT) genotype in the posterior cingulate, cuneus, precuneus and putamen. Moreover, higher body mass index in the AA genotype was associated with reduced activity to food images in areas important for emotion (cingulate cortex), but also in areas important for impulse control (frontal gyri and lentiform nucleus). Lastly, we corroborate our findings with behavioural scales for the behavioural inhibition and activation systems. Our results suggest that the two genotypes are associated with differential neural processing of food images, which may influence weight status through diminished impulse control and reward processing.

Visual perceptions of male obesity: a cross-cultural study examining male and female lay perceptions of obesity in Caucasian males.

BACKGROUND: Obesity is now common and this may have altered visual perceptions of what constitutes a 'normal' and therefore healthy weight. The present study examined cross-cultural differences in male and female participants' ability to visually identify the weight status of photographed Caucasian males. METHODS: Five hundred and fifty three male and female young adults from the US (high obesity prevalence), UK and Sweden (lower obesity prevalence) participated in an online study. Participants judged the weight status of a series of photographed healthy weight, overweight and obese (class I) Caucasian males and rated the extent to which they believed each male should consider losing weight. RESULTS: There was a strong tendency for both male and female participants to underestimate the weight status of the photographed overweight and obese males. Photographed males were frequently perceived as being of healthier weight than they actually were. Some modest cross-cultural differences were also observed; US participants were worse at recognising obesity than UK participants (p < 0.05) and were also significantly more likely to believe that the photographed obese males did not need to consider losing weight, in comparison to both the UK and Swedish participants (ps < 0.05). No cross-cultural differences were observed for perceptions or attitudes towards the photographed healthy weight or overweight males. CONCLUSIONS: The weight status of overweight and obese (class I) Caucasian males is underestimated when judged by males and females using visual information alone. This study provides initial evidence of modest cross-cultural differences in attitudes toward, and the ability to recognise, obesity in Caucasian males.

Self-reported sleep disturbance is associated with Alzheimer's disease risk in men.

OBJECTIVE: To study the association between self-reported sleep disturbances and dementia risk. METHODS: Self-reported sleep disturbances and established risk factors for dementia were measured in men at ages 50 (n = 1574) and 70 (n = 1029) years. Dementia incidence was determined by reviewing their patient history between ages 50 and 90 years. In addition, plasma levels of ß-amyloid (Aß) peptides 1-40 and 1-42 were measured at ages 70, 77, and 82 years. RESULTS: Cox regression demonstrated that men with self-reported sleep disturbances had a higher risk of developing dementia (+33%) and Alzheimer's disease (AD, +51%) than men without self-reported sleep disturbances (both P < .05). Binary logistic regression showed the increased risk for both dementia (+114%) and AD (+192%) were highest when sleep disturbance was reported at age 70 years (both P < .001). No group differences were found in Aß levels. CONCLUSION: Improving sleep quality may help reduce the neurodegenerative risk in older men.

Expected satiation after repeated consumption of low- or high-energy-dense soup.

We investigated whether repeated consumption of a low-energy-dense (LED; 208 kJ/100 g) or high-energy-dense (HED; 645 kJ/100 g) soup modifies expectations relating to the satiating capacity of the food, and its subsequent intake. In study 1, participants consumed either a novel-flavoured LED (n 32; 21 (SD 1·6) years, BMI 21·4 (SD 1·6) kg/m(2)) or HED soup (n 32; 21 (SD 1·6) years, BMI 21·3 (SD 1·7) kg/m(2)). Soup was served in a fixed amount on days 1-4 and ad libitum on day 5. 'Expected satiation' was measured on days 1, 2 and 5. Expected satiation did not change after repeated consumption of the LED or HED soup. Ad libitum intake did not differ between the LED (461 (SD 213) g) and HED soup (391 (SD 164) g). Only on day 1, expected satiation was higher for the HED soup than for the LED soup (P = 0·03), suggesting a role for sensory attributes in expected satiation. In study 2, thirty participants (21 (SD 1·6) years, BMI 21·3 (SD 1·7) kg/m(2)) performed a single measurement of expected satiation of the LED and HED soup, and four commercially available types of soup. Ratings on sensory attributes were associated with expected satiation. Results on expected satiation coincided with those of study 1. Thickness and intensity of taste were independently associated with expected satiation. Expectations may initially rely on sensory attributes and previous experiences, and are not easily changed.

Taste of a 24-h diet and its effect on subsequent food preferences and satiety.

The objective of this study was to investigate the effect of taste of a 24-h diet on subsequent food preferences (food choice and intake of specific food categories) and satiety. We used a crossover design, consisting of a 24-h fully controlled dietary intervention, during which 39 healthy subjects consumed diets that were predominantly sweet tasting, savory tasting, or a mixture. The diets were similar in energy content, macronutrient composition, and number of different products used. Following the intervention an ad libitum lunch buffet was offered the next day, consisting of food items differing in taste (sweet/savory) and protein content (low/high) and intake was measured. The results showed that the taste of the diet significantly altered preference for food according to their taste properties (p<0.0001); after the savory diet, intake of sweet foods was higher than of savory foods. After the sweet diet, savory foods tended to be preferred (p=0.07). No interaction was seen between the taste of the diet and food preference according to their protein content (p=0.67). No differences in total energy intake (kJ) at the ad libitum lunch buffet were observed (p=0.58). It appears that in healthy subjects, taste of a 24-h diet largely affects subsequent food preferences in terms of sensory appetite, whereby savory taste exerts the strongest modulating effect. Taste of a 24-h diet has no effect on macronutrient appetite.

Texture, not flavor, determines expected satiation of dairy products.

Consumers' expectations about the satiating capacity of a food may differ markedly across a broad range of food products, but also between foods within one product category. Our objective is to investigate the role of sensory attributes and means of consumption in the expected satiation of dairy products. In three independent experiments we measured the expected satiation of (1) commercially available yogurts and custards (29 adults, age: 26 ± 5 y, BMI: 22.9 ± 2.4 kg/m(2)); (2) lemon- and meringue-flavored custards with different textures (30 adults, age: 23 ± 4 y, BMI: 22.1 ± 2.1 kg/m(2)); and (3) chocolate milk and chocolate custard consumed with either a straw or a spoon (30 adults, age: 20 ± 2.2 y, BMI: 21.5 ± 2.2 kg/m(2)); all based on a single mouthful. Expected satiation was linked to the product's perceived characteristics. We observed an effect of texture (p<0.0001), but not of flavor on expected satiation (p=0.98) in Experiment 2; and an effect of texture (p<0.0001), but not of means of consumption on expected satiation (p=0.63) in Experiment 3. Thickness was positively correlated with expected satiation in Experiment 1 (r=0.45; p<0.001) and Experiment 2 (r=0.54; p<0.001). Expected satiation of dairy products increased consistently with increasing thickness; flavor characteristics or means of consumption as tested did not change expected satiation effects.

Postprandial alterations in whole-blood DNA methylation are mediated by changes in white blood cell composition.

BACKGROUND: DNA methylation is an essential nuclear process associated with genomic functions such as transcription factor binding and the regulation of gene expression. DNA methylation patterns can also serve as potential biomarkers for disease progression and response to therapy. However, the full dynamics of DNA methylation across daily physiologic events have not been fully elucidated. OBJECTIVE: We sought to study how ingesting a standardized meal acutely affects peripheral blood DNA methylation. DESIGN: We performed an observational study in healthy men (n = 26) on DNA methylation and gene expression in whole blood before and 160 min after the ingestion of a standardized meal. Cytosine-phosphate-guanine (CpG) methylation was assayed on the HumanMethylation450k microarray, and gene expression was measured with the Human Gene 2.1 ST Array. RESULTS: Differential methylation after food intake was detected in 13% of the analyzed probes (63,207 CpG probes) at a 5% false discovery rate (FDR). This effect was driven by changes in leukocyte fractions as estimated from comparisons against methylation datasets generated from sorted leukocytes. When methylation values were adjusted for estimated leukocyte fractions, 541 probes were observed to be altered in the postprandial state (5% FDR). CONCLUSIONS: Apparent alterations in DNA methylation 160 min after meal ingestion mainly reflect changes in the estimated leukocyte population in whole blood. These results have major methodologic implications for genome-wide methylation studies because they highlight the strong underlying effects of changes in leukocyte fractions on CpG methylation patterns as well as the potential importance of meal-standardized sampling procedures for future investigations when alterations in white blood cell fractions are unavailable. This trial was registered at clinicaltrials.gov as LSF008786.

Associations of self-reported sleep disturbance and duration with academic failure in community-dwelling Swedish adolescents: sleep and academic performance at school.

OBJECTIVE: To examine associations of self-reported sleep disturbance and short sleep duration with the risk for academic failure. METHODS: A cohort of ~40,000 adolescents (age range: 12-19 years) who were attending high school grades 7, 9, and 2nd year of upper secondary school in the Swedish Uppsala County were invited to participate in the Life and Health Young Survey (conducted between 2005 and 2011 in Uppsala County, Sweden). In addition to the question how many subjects they failed during the school year (outcome variable), subsamples of adolescents also answered questions related to subjective sleep disturbance (n = 20,026) and habitual sleep duration (n = 4736) (exposure variables). Binary logistic regression analysis was utilized to explore if self-reported sleep disturbances and habitual short sleep duration (defined as less than 7-8 h sleep per night) increase the relative risk to fail subjects during the school year (controlled for possible confounders, e.g. body-mass-index). RESULTS: Adolescents with self-reported sleep disturbances had an increased risk for academic failure (i.e., they failed at least one subject during the school year; OR: boys, 1.68; girls, 2.05, both P < 0.001), compared to adolescents without self-reported sleep disturbances. In addition, adolescents who reported short sleep duration on both working and weekend days were more likely to fail at least one subject at school than those who slept at least 7-8 h per night (OR: boys, 4.1; girls, 5.0, both P < 0.001). CONCLUSION: Our findings indicate that reports of sleep disturbance and short sleep duration are linked to academic failure in adolescents. Based on our data, causality cannot be established.

Patients lacking sustainable long-term weight loss after gastric bypass surgery show signs of decreased inhibitory control of prepotent responses.

BACKGROUND: A considerable number of bariatric patients report poor long-term weight loss after Roux-en-Y gastric bypass (RYGB) surgery. One possibility for an underlying cause is an impairment of cognitive control that impedes this patient group's dietary efforts. OBJECTIVE: To investigate if patients having either poor or good weight loss response, ~12 years after RYGB-surgery, differ in their ability to inhibit prepotent responses when processing food cues during attentional operations-as measure of cognitive control. METHODS: In terms of weight loss following RYGB-surgery, 15 'poor responders' and 15 'good responders', matched for gender, age, education, preoperative body mass index, and years since surgery, were administered two tasks that measure sustained attention and response control: a go/no-go task and a Stroop interference task; both of which are associated with maladaptive eating behaviours. RESULTS: The poor responders (vs. good responders) needed significantly more time when conducting a go/no-go task (603±134 vs. 519±44 msec, p = 0.03), but the number of errors did not differ between groups. When conducting a Stroop interference task, poor responders read fewer inks than good responders (68±16 vs. 85±10 words, p = 0.002). CONCLUSION: Patients lacking sustainable weight loss after RYGB-surgery showed poorer inhibitory control than patients that successfully lost weight. In the authors' view, these results suggest that cognitive behavioral therapies post-RYGB-surgery may represent a promising behavioral adjuvant to achieve sustainable weight loss in patients undergoing this procedure. Future studies should examine whether these control deficits in poor responders are food-specific or not.

Are You Sure? Confidence about the Satiating Capacity of a Food Affects Subsequent Food Intake.

Expectations about a food's satiating capacity predict self-selected portion size, food intake and food choice. However, two individuals might have a similar expectation, but one might be extremely confident while the other might be guessing. It is unclear whether confidence about an expectation affects adjustments in energy intake at a subsequent meal. In a randomized cross-over design, 24 subjects participated in three separate breakfast sessions, and were served a low-energy-dense preload (53 kcal/100 g), a high-energy-dense preload (94 kcal/100 g), or no preload. Subjects received ambiguous information about the preload's satiating capacity and rated how confident they were about their expected satiation before consuming the preload in its entirety. They were served an ad libitum test meal 30 min later. Confidence ratings were negatively associated with energy compensation after consuming the high-energy-dense preload (r = -0.61; p = 0.001). The same relationship was evident after consuming the low-energy-dense preload, but only after controlling for dietary restraint, hunger prior to, and liking of the test meal (p = 0.03). Our results suggest that confidence modifies short-term controls of food intake by affecting energy compensation. These results merit consideration because imprecise caloric compensation has been identified as a potential risk factor for a positive energy balance and weight gain.

Late-life alcohol consumption and cognitive function in elderly men.

Moderate alcohol consumption (one to two drinks per day) has been associated with better cognitive function and lower risk of developing dementia in the elderly. In light of alcohol's well-known neurotoxic properties, more evidence from well-controlled population-based studies is required. The objective of this study was to examine whether self-reported alcohol intake at age 70 is linked to cognitive function (assessed by trail making tests (TMTs) A and B, which are measures of attention, mental speed, and flexibility) in a population-based cohort consisting of 652 cognitively healthy elderly men. Linear regression models were used to assess both cross-sectional (i.e., age 70) and prospective (i.e., age 77) associations between alcohol intake and cognitive function. The analyses were adjusted for education, body mass index, energy intake, self-reported physical activity, smoking, a history of hypertension or diabetes, apolipoprotein E ε4 status, and cholesterol levels at the age of 70. Baseline data were obtained from 1990 to 1996. Self-reported alcohol intake (mean 6.9 ± 7.1 g/day) was associated with better performance on TMT-B at ages 70 and 77 (ß = -0.87, p < 0.001). In contrast, alcohol intake was not predictive of the difference in performance on these tests between ages 70 and 77. Despite cross-sectional associations with performance in a test of executive functioning, moderate intake of alcohol was not linked to differences in cognitive performance between ages 70 and 77 in the present study. Thus, our findings do not support the view that daily moderate alcohol consumption is a recommendable strategy to slow cognitive aging in elderly populations.

Watching TV and food intake: the role of content.

Obesity is a serious and growing health concern worldwide. Watching television (TV) represents a condition during which many habitually eat, irrespective of hunger level. However, as of yet, little is known about how the content of television programs being watched differentially impacts concurrent eating behavior. In this study, eighteen normal-weight female students participated in three counter-balanced experimental conditions, including a 'Boring' TV condition (art lecture), an 'Engaging' TV condition (Swedish TV comedy series), and a no TV control condition during which participants read (a text on insects living in Sweden). Throughout each condition participants had access to both high-calorie (M&Ms) and low-calorie (grapes) snacks. We found that, relative to the Engaging TV condition, Boring TV encouraged excessive eating (+52% g, P = 0.009). Additionally, the Engaging TV condition actually resulted in significantly less concurrent intake relative to the control 'Text' condition (-35% g, P = 0.05). This intake was driven almost entirely by the healthy snack, grapes; however, this interaction did not reach significance (P = 0.07). Finally, there was a significant correlation between how bored participants were across all conditions, and their concurrent food intake (beta = 0.317, P = 0.02). Intake as measured by kcals was similarly patterned but did not reach significance. These results suggest that, for women, different TV programs elicit different levels of concurrent food intake, and that the degree to which a program is engaging (or alternately, boring) is related to that intake. Additionally, they suggest that emotional content (e.g. boring vs. engaging) may be more associated than modality (e.g. TV vs. text) with concurrent intake.

Increased impulsivity in response to food cues after sleep loss in healthy young men.

OBJECTIVE: To investigate whether acute total sleep deprivation (TSD) leads to decreased cognitive control when food cues are presented during a task requiring active attention, by assessing the ability to cognitively inhibit prepotent responses. METHODS: Fourteen males participated in the study on two separate occasions in a randomized, crossover within-subject design: one night of TSD versus normal sleep (8.5 hours). Following each nighttime intervention, hunger ratings and morning fasting plasma glucose concentrations were assessed before performing a go/no-go task. RESULTS: Following TSD, participants made significantly more commission errors when they were presented "no-go" food words in the go/no-go task, as compared with their performance following sleep (+56%; P<0.05). In contrast, response time and omission errors to "go" non-food words did not differ between the conditions. Self-reported hunger after TSD was increased without changes in fasting plasma glucose. The increase in hunger did not correlate with the TSD-induced commission errors. CONCLUSIONS: Our results suggest that TSD impairs cognitive control also in response to food stimuli in healthy young men. Whether such loss of inhibition or impulsiveness is food cue-specific as seen in obesity-thus providing a mechanism through which sleep disturbances may promote obesity development-warrants further investigation.

Acute sleep deprivation increases serum levels of neuron-specific enolase (NSE) and S100 calcium binding protein B (S-100B) in healthy young men.

STUDY OBJECTIVES: To investigate whether total sleep deprivation (TSD) affects circulating concentrations of neuron-specific enolase (NSE) and S100 calcium binding protein B (S-100B) in humans. These factors are usually found in the cytoplasm of neurons and glia cells. Increasing concentrations of these factors in blood may be therefore indicative for either neuronal damage, impaired blood brain barrier function, or both. In addition, amyloid ß (Aß) peptides 1-42 and 1-40 were measured in plasma to calculate their ratio. A reduced plasma ratio of Aß peptides 1-42 to 1-40 is considered an indirect measure of increased deposition of Aß 1-42 peptide in the brain. DESIGN: Subjects participated in two conditions (including either 8-h of nocturnal sleep [22:30-06:30] or TSD). Fasting blood samples were drawn before and after sleep interventions (19:30 and 07:30, respectively). SETTING: Sleep laboratory. PARTICIPANTS: 15 healthy young men. RESULTS: TSD increased morning serum levels of NSE (P = 0.002) and S-100B (P = 0.02) by approximately 20%, compared with values obtained after a night of sleep. In contrast, the ratio of Aß peptides 1-42 to 1-40 did not differ between the sleep interventions. CONCLUSIONS: Future studies in which both serum and cerebrospinal fluid are sampled after sleep loss should elucidate whether the increase in serum neuron-specific enolase and S100 calcium binding protein B is primarily caused by neuronal damage, impaired blood brain barrier function, or is just a consequence of increased gene expression in non-neuronal cells, such as leukocytes.

Acute sleep deprivation increases food purchasing in men.

OBJECTIVE: To investigate if acute sleep deprivation affects food purchasing choices in a mock supermarket. DESIGN AND METHODS: On the morning after one night of total sleep deprivation (TSD) or after one night of sleep, 14 normal-weight men were given a fixed budget (300 SEK-approximately 50 USD). They were instructed to purchase as much as they could out of a possible 40 items, including 20 high-caloric foods (>2 kcal/g) and 20 low-caloric foods (<2 kcal/g). The prices of the high-caloric foods were then varied (75%, 100% (reference price), and 125%) to determine if TSD affects the flexibility of food purchasing. Before the task, participants received a standardized breakfast, thereby minimizing the potential confound produced by hunger. In addition, morning plasma concentrations of the orexigenic hormone ghrelin were measured under fasting conditions. RESULTS: Independent of both type of food offered and price condition, sleep-deprived men purchased significantly more calories (+9%) and grams (+18%) of food than they did after one night of sleep (both P < 0.05). Morning plasma ghrelin concentrations were also higher after TSD (P < 0.05). However, this increase did not correlate with the effects of TSD on food purchasing. CONCLUSIONS: This experiment demonstrates that acute sleep loss alters food purchasing behavior in men.

Acute sleep deprivation increases portion size and affects food choice in young men.

Acute sleep loss increases food intake in adults. However, little is known about the influence of acute sleep loss on portion size choice, and whether this depends on both hunger state and the type of food (snack or meal item) offered to an individual. The aim of the current study was to compare portion size choice after a night of sleep and a period of nocturnal wakefulness (a condition experienced by night-shift workers, e.g. physicians and nurses). Sixteen men (age: 23 ± 0.9 years, BMI: 23.6 ± 0.6 kg/m(2)) participated in a randomized within-subject design with two conditions, 8-h of sleep and total sleep deprivation (TSD). In the morning following sleep interventions, portion size, comprising meal and snack items, was measured using a computer-based task, in both fasted and sated state. In addition, hunger as well as plasma levels of ghrelin were measured. In the morning after TSD, subjects had increased plasma ghrelin levels (13%, p=0.04), and chose larger portions (14%, p=0.02), irrespective of the type of food, as compared to the sleep condition. Self-reported hunger was also enhanced (p<0.01). Following breakfast, sleep-deprived subjects chose larger portions of snacks (16%, p=0.02), whereas the selection of meal items did not differ between the sleep interventions (6%, p=0.13). Our results suggest that overeating in the morning after sleep loss is driven by both homeostatic and hedonic factors. Further, they show that portion size choice after sleep loss depend on both an individual's hunger status, and the type of food offered.

Intake during repeated exposure to low- and high-energy-dense yogurts by different means of consumption.

BACKGROUND: An important question in the regulation of energy intake is whether dietary learning of energy content depends on the food's characteristics, such as texture. Texture might affect the duration of sensory exposure and eating rate. OBJECTIVE: The objective was to investigate whether a long sensory exposure, due to differences in means of consumption and in viscosity, enhances learned associations between sensory signals and metabolic consequences and hence facilitates energy intake compensation. DESIGN: A total of 105 healthy young adults with a mean (+/-SD) age of 22 +/- 3 y and a body mass index (in kg/m(2)) of 21.6 +/- 1.7 participated in a parallel intervention in 3 groups: liquid yogurt with a straw (liquid/straw; n = 34), liquid yogurt with a spoon (liquid/spoon; n = 36), or semisolid yogurt with a spoon (semisolid/spoon; n = 35). Novel flavored yogurts were offered ad libitum for breakfast in 2 energy densities: low ( approximately 215 kJ/100 g) and high ( approximately 600 kJ/100 g). Subjects were repeatedly exposed to the yogurt products (10 times), and yogurt intake was measured. RESULTS: Intakes (P = 0.01) and eating rates (P = 0.01) were highest in the liquid/straw group. Average intakes over 10 exposures were 575 +/- 260 g for liquid/straw, 475 +/- 192 g for liquid/spoon, and 470 +/- 223 g for semisolid/spoon; average eating rates were 132 +/- 83 g/min for liquid/straw, 106 +/- 53 g/min for liquid/spoon, and 105 +/- 88 g/min for semisolid/spoon. No significant interaction for intake between intervention group, energy density, and repeated exposure was observed, and intakes of the low- and high-energy-dense yogurts did not change over time in any of the intervention groups. CONCLUSIONS: We observed no energy intake compensation after repeated exposure to yogurt products. Differences in ad libitum yogurt intake could be explained by eating rate, which was affected by the different means of consumption. This trial was registered with the Dutch trial registration at http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1853 as NTR1853.