Jessica McNeil

Inadequate Sleep as a Contributor to Obesity and Type 2 Diabetes

Epidemiological studies suggest that adults and children who are habitual short sleepers tend to have a higher body mass index, fat percentage and abdominal circumference when compared to average-duration sleepers. Reduced or disturbed sleep is also associated with certain predictors of type 2 diabetes, such as glucose intolerance, insulin resistance, reduced insulin response to glucose and a reduction in the disposition index. Current experimental evidence suggests that sleep restriction may lead to increased food intake but does not appear to result in decreased energy expenditure. Furthermore, sleep restriction has been reported to increase evening cortisol levels, which may decrease insulin sensitivity the next morning. This notion was further supported by studies, which noted decreases in the effectiveness of insulin-mediated glucose uptake the following morning. Further evidence suggests that short sleepers have glucose responses that are similar to average-duration sleepers, but at the cost of an increase in insulin release, which may be the result of decreased insulin sensitivity over time. Recent studies also provide evidence that sleep restriction enhances susceptibility to food stimuli, especially for energy-dense, high-carbohydrate foods. In summary, inadequate sleep, in both quality and quantity, should be regarded as a plausible risk factor for the development of obesity and type 2 diabetes. In addition to other health promotion measures, a good nights sleep should be seen as a critical health component by clinicians in the prevention and treatment of obesity and type 2 diabetes.

Short sleep duration as a risk factor for the development of the metabolic syndrome in adults.

OBJECTIVE The objective of this study was to investigate the association between self-reported sleep duration and the incidence of features of the metabolic syndrome in adults. METHODS A longitudinal analysis from the Quebec Family Study (Canada) was conducted on 293 participants, aged 18 to 65 years, followed for a mean of 6 years (until 2001). Participants were categorized as short (≤6 h), adequate (7-8 h) or long (≥9 h) sleepers. The metabolic syndrome was defined according to the American Heart Association/National Heart, Lung, and Blood Institutes criteria. The hypertriglyceridemic waist phenotype was defined as high waist circumference (≥90 cm in men and ≥85 cm in women) combined with high fasting triglyceride level (≥2.0 mmol/L in men and ≥1.5 mmol/L in women). RESULTS The incidence rates of metabolic syndrome and hypertriglyceridemic waist phenotype were 9.9% and 7.5%, respectively. Short sleepers were significantly more at risk of developing the metabolic syndrome (relative risk (RR): 1.74; 95% confidence interval (CI): 1.05-2.72) and the hypertriglyceridemic waist phenotype (RR: 1.82; 95% CI: 1.16-2.79), compared to those sleeping 7 to 8h per night after adjusting for covariates. However, long sleep duration was not associated with an increased risk of developing the metabolic syndrome or the hypertriglyceridemic waist phenotype (either unadjusted or adjusted models). CONCLUSION Short sleep duration is associated with an increased risk of developing features of the metabolic syndrome in adults.

Short sleep duration is associated with greater alcohol consumption in adults.

The objective of this cross-sectional study was to examine the association between sleep duration and alcohol consumption in adults (301 men and 402 women aged 18-64years) from the greater Quebec City area. Sleep duration (self-reported), alcohol consumption (3-day food record and questions on drinking habits), and disinhibition eating behavior trait (score ≥ 6 on the Three-Factor Eating Questionnaire) were assessed. Participants were categorized as short- ( ≤ 6h), average- (7-8h) or long- ( ≥ 9h) duration sleepers. Overall, short-duration sleepers consumed significantly more alcohol than the two other sleep-duration groups. After adjusting for relevant covariates, short sleep duration was associated with an increase in the odds of exceeding the recommendations for sensible weekly alcohol intake of 14 drinks for men and 7 drinks for women compared to those sleeping between 7 and 8h (OR 1.87, 95%CI 1.03-3.54, both sexes combined). In both men and women, daily alcohol intake was significantly higher in short-duration sleepers having a high disinhibition eating behavior trait. However, the prevalence of a binge drinking occasion (i.e. ≥5 drinks on one occasion) was more common in men than women. Men sleeping less than 6h per night with a disinhibited eating behavior were more likely to report binge drinking (41% of them). In summary, the combination of short sleep duration with disinhibited eating behavior is associated with greater alcohol intake in adults.

Possible factors for altered energy balance across the menstrual cycle: a closer look at the severity of PMS, reward driven behaviors and leptin variations

This paper reviews the literature on the variations in energy intake (EI), energy expenditure (EE) and the factors which may affect the fluctuations in EI across the menstrual cycle. While no significant changes in body weight and body fat percentage have been noted across the cycle, increases in EI and EE have been well documented during the luteal phase in lean women. The occurrence and severity of the premenstrual syndrome (PMS) and food reinforcement are suggested to affect EI. It is not known, however, whether food reinforcement may affect EI across the menstrual cycle. These factors may also affect overweight/obese women differently than normal-weight women at times during which women may be more prone to episodes of overeating during the menstrual cycle. Certain studies have also noted fluctuations in leptin levels across the menstrual cycle, while others have not. It has also been suggested that variations in leptin levels may affect the rewarding value of food in order to maintain proper body weight and adiposity level. We emphasize that future studies should evaluate the variations in energy balance across the cycle in overweight/obese women, as well as the strength of the relationships between food reinforcement and the severity of PMS with energy and macronutrient intakes.

Objectively-measured sleep and its association with adiposity and physical activity in a sample of Canadian children

Cross‐sectional associations between objectively‐measured sleep duration, sleep efficiency and sleep timing with adiposity and physical activity were examined in a cohort of 567 children from Ottawa, Canada. Five‐hundred and fifteen children (58.8% female; age: 10.0 ± 0.4 years) had valid sleep measurements and were included in the present analyses. Physical activity, sedentary time and sleep parameters were assessed over 7 days (actigraphy). Height, weight and waist circumference were measured according to standardized procedures. Percentage body fat was assessed using bioelectric impedance analysis. Light physical activity and sedentary time were greater in children with the shortest sleep durations (P < 0.0001), whereas children with the highest sleep efficiencies had lower light physical activity and more sedentary time across tertiles (P < 0.0001). In multivariable linear regression analyses, and after adjusting for a number of covariates, sleep efficiency was inversely related to all adiposity indices (P < 0.05). However, sleep duration and sleep timing were not associated with adiposity indices after controlling for covariates. Inverse associations were noted between sleep duration and light physical activity and sedentary time (P < 0.0001). Sleep efficiency (P < 0.0001), wake time and sleep timing midpoint (P < 0.05) were negatively associated with light physical activity, but positively associated with sedentary time. In conclusion, only sleep efficiency was independently correlated with adiposity in this sample of children. Participants with the shortest sleep durations or highest sleep efficiencies had greater sedentary time. More research is needed to develop better sleep recommendations in children that are based on objective measures of sleep duration, sleep efficiency and sleep timing alike.

Seven to eight hours of sleep a night is associated with a lower prevalence of the metabolic syndrome and reduced overall cardiometabolic risk in adults.

Background Previous studies looking at the relationship between sleep duration and the metabolic syndrome have only used a dichotomous approach (presence/absence) and failed to adjust for important confounding factors. The objective of the present study was to examine the association between self-reported sleep duration and features of the metabolic syndrome in adults. Methods A cross-sectional analysis from the Quebec Family Study (Canada) was conducted on 810 participants aged 18 to 65 years. Participants were categorized as short (≤6 h), adequate (7–8 h) or long (≥9 h) sleepers. The metabolic syndrome was defined according to the American Heart Association/National Heart, Lung, and Blood Institute’s criteria. Results Overall, 24.6% of the sample had the metabolic syndrome. A U-shaped relationship between sleep duration and the prevalence of metabolic syndrome (33.3%, 22.0% and 28.8% in short, adequate and long sleepers, respectively) was observed (P<0.01). Only short sleepers had a significant increase in the odds of having the metabolic syndrome (OR = 1.76, 95% CI = 1.08–2.84) compared to adequate sleepers after adjustment for age, sex, smoking habits, highest education level, total annual family income, alcohol consumption, coffee intake, menopausal status, daily caloric intake, and moderate-to-vigorous physical activity. Likewise, the clustered cardiometabolic risk score (i.e. continuous risk score based on the metabolic syndrome components) was significantly higher in short sleepers compared to adequate sleepers after adjustment for covariates (P<0.05). Conclusion Sleeping ≤6 h per night is associated with an elevated cardiometabolic risk score and an increase in the odds of having the metabolic syndrome after adjusting for possible confounders. These results strongly suggest that short sleep duration is a risk factor for the metabolic syndrome.

Reproducibility of a food menu to measure energy and macronutrient intakes in a laboratory and under real-life conditions.

Given the limitations associated with the measurement of food intake, we aimed to determine the reliability of a food menu to measure energy intake (EI) and macronutrient intake within the laboratory and under free-living conditions. A total of eight men and eight women (age 25·74 (sd 5·9) years, BMI 23·7 (sd 2·7) kg/m²) completed three identical in-laboratory sessions (ILS) and three out-of-laboratory sessions (OLS). During the ILS, participants had ad libitum access to a variety of foods, which they chose from a menu every hour, for 5 h. For the OLS, the foods were chosen from the menu at the start of the day and packed into containers to bring home. There were no significant differences in total EI (6118·6 (sd 2691·2), 6678·8 (sd 2371·3), 6489·5 (sd 2742·9) kJ; NS) between the three ILS and three OLS (6816·0 (sd 2713·2), 6553·5 (sd 2364·5), 6456·4 (sd 3066·8) kJ; NS). Significant intraclass correlations (ICC) for total energy (r 0·77, P<0·0001), carbohydrate (r 0·81, P<0·0001), dietary fat (r 0·54, P<0·0001) and protein (r 0·81, P<0·0001) intakes for the ILS and significant ICC for total energy (r 0·85, P<0·0001), carbohydrate (0·85, P<0·0001), dietary fat (0·72 P<0·0001) and protein (0·80, P<0·0001) intakes for the OLS were noted. The average within-subject CV for total EI was 18·3 (sd 10·0) and 16·1 (sd 10·3) % for the ILS and OLS, respectively, with a pleasantness rating for foods consumed of 124 (sd 14) mm out of 150 mm (83 %). Overall, the food menu produces a relatively reliable measure of EI inside and outside the laboratory. The results also underscore the difficulties in capturing a representative image of food intake given the relatively high day-to-day variation in the amount and composition of foods consumed.

Greater overall olfactory performance, explicit wanting for high fat foods and lipid intake during the mid-luteal phase of the menstrual cycle

Increases in energy, lipid and carbohydrate intakes during the luteal phase have been previously observed. However, it is not known whether this is due to phase-dependent variations in the reward value of certain foods. Moreover, increases in olfactory sensitivity have been proposed and may be involved in these changes in food reward. Therefore, we examined olfactory performance and the reward value of foods varying in fat content and taste. Seventeen women (Body mass index: 22.3±1.6 kg/m(2); Body fat-DXA: 28.5±6.8%) were recruited to participate in 3 identical sessions, performed during distinct phases of the menstrual cycle - early follicular/menstruation, late follicular/ovulation and mid-luteal - verified by plasma sex-steroid hormones and oral temperature. Food preference, implicit wanting, and explicit wanting and liking for visual food cues, varying in fat content and taste, were measured with a validated experimental platform involving a forced choice computer task. Odour threshold, odour discrimination, odour identification and total odour scores were measured using odourized pens. Ad libitum energy and macronutrient intake was measured with a validated food menu. Results showed greater total odour scores (p<0.05), explicit wanting for high fat foods (p<0.05) and lipid intake (p<0.05) during the mid-luteal phase. Inter-correlations between these variables were non-significant. These findings support previous observations of increased lipid intake during the luteal phase and provide evidence for phase-dependent variation in overall olfactory performance and explicit wanting for high fat foods.

Active video games and energy balance in male adolescents: a randomized crossover trial

BACKGROUND Active video games (AVGs) have been shown to acutely increase energy expenditure when compared with seated video games; however, the influence of AVGs on compensatory adjustments in energy intake and expenditure is largely unknown. OBJECTIVE The aim was to examine the acute effects of AVGs on energy intake and expenditure. DESIGN With the use of a randomized crossover design, 26 male adolescents (mean ± SD age: 14.5 ± 1.4 y) completed three 1-h experimental conditions: resting control, seated video game play (Xbox 360; Microsoft), and AVG play (Kinect Adventures on Xbox 360) followed by an ad libitum lunch. A validated food menu was used to assess food intake immediately after the conditions and for the remainder of the day, and a dietary record was used for the subsequent 3-d period. Energy expenditure was measured by using portable indirect calorimetry throughout each experimental condition, and an accelerometer was used to assess the subsequent 3-d period. Appetite sensations were assessed by using visual analog scales at different time points during the testing day. The primary outcomes were acute (immediately after the conditions and 24-h) and short-term (3-d) energy intake and expenditure. RESULTS Energy expenditure was significantly higher (~145%; P < 0.001) during the AVG condition than during the resting control and seated video game conditions; however, no significant differences in energy expenditure were observed 24 h (~6%; P > 0.49) and 3 d after the experimental conditions (~3%; P > 0.82). No significant differences were observed in absolute energy intake immediately after the conditions (~2%; P > 0.94) or in absolute energy intake 24 h (~5%; P > 0.63) and 3 d (~9%; P > 0.53) after the experimental conditions. Finally, appetite sensations were similar between conditions at all time points (P > 0.05). CONCLUSIONS The increase in energy expenditure promoted by a single session of Kinect AVG play is not associated with increased food intake but is compensated for after the intervention, resulting in no measurable change in energy balance after 24 h. These results suggest that the potential of Kinect to reduce the energy gap underlying weight gain is offset within 24 h in male adolescents. This trial was registered at clinicaltrials.gov as NCT01655901.

Resistance and aerobic exercises do not affect post-exercise energy compensation in normal weight men and women.

BACKGROUND Previous research has reported no effect of exercise modality (aerobic vs. resistance) on energy intake (EI). However, the relatively low energy cost of resistance training, the absence of total energy expenditure (TEE) measurements and the short duration of these studies justify further investigation. OBJECTIVE To evaluate the effects of exercise modality on EI, TEE, non-exercise activity thermogenesis (NEAT) and post-exercise energy compensation (PEEC) measured acutely, as well as for 10 and 34 h following exercise. DESIGN Eight men and 8 women participated in three randomized crossover sessions: aerobic-based exercise, resistance-based exercise, and sedentary control. Exercise energy expenditure (ExEE) was continuously measured (indirect calorimetry) throughout the exercise sessions, which were designed to produce an isocaloric ExEE of 4 kcal/kg body weight. TEE and EI were monitored for 34 h post-exercise with biaxial accelerometers and a validated food menu, respectively. RESULTS There were no differences in EI between exercise modalities acutely, as well as 10 and 34 h following exercise. However, a modality by sex interaction was noted for acute EI. Men ate more after the resistance than after the aerobic session (1567±469; 1255±409 kcal, respectively; P=0.034), while no differences were seen in women (568±237; 648±270 kcal, respectively; P=NS). No differences in TEE, NEAT and PEEC were found 10h and 34 h post-exercise, while a positive correlation (r=0.897; P<0.01) was found between both modalities across participants for PEEC. CONCLUSION Exercise modality does not impact PEEC when ExEE is controlled. Our results also show that within-individual PEEC seems to be relatively constant across exercise modality.