Nicola J. Buckland

Disentangling the relationship between sedentariness and obesity: Activity intensity, but not sitting posture, is associated with adiposity in women

BACKGROUND The relationship between free-living sedentary behaviour (SB) and obesity is unclear. Studies may arrive at disparate conclusions because of inconsistencies and limitations when defining and measuring free-living SB. The aim of this cross-sectional study was to examine whether the relationship between SB and adiposity differed depending on the way SB was operationally defined and objectively measured. METHODS Sixty-three female participants aged 37.1 years (SD = 13.6) with a body mass index (BMI) of 29.6 kg/m2 (SD = 4.7) had their body composition measured (BodPod, Concord, CA) then were continuously monitored for 5-7 days with the SenseWear Armband (SWA; sleep and activity intensity) and the activPAL (AP; posture). Data from both activity monitors were analysed separately and integrated resulting in a third measure of SB (activity intensity and posture; SEDINT). SB outputs were compared according to week or weekend day averages then correlated against body composition parameters after adjusting for moderate-to-vigorous physical activity (MVPA). RESULTS SEDSWA resulted in the most sedentary time 11.74 h/day (SD = 1.60), followed by SEDAP 10.16 h/day (SD = 1.75) and SEDINT 9.10 h/day (SD = 1.67). There was a significant positive association between SEDSWA and body mass [r(61) = 0.29, p = .02], BMI [r (61) = 0.33, p = .009] and fat mass [r(61) = 0.32, p = .01]. SEDAP and SEDINT were not associated with any of the indices of adiposity. Correlations between SB and adiposity were non-significant when controlling for MVPA. CONCLUSIONS The relationship between SB and adiposity differed depending on how SB was operationally defined and measured, and was dependent on MVPA. The definition of SB based on a sitting posture (SEDAP) was not strongly related to body fat, whereas the accumulation of any behaviour (sitting or standing) with an intensity of <1.5 METs (SEDSWA) (offset by the presence of MVPA) was positively associated with indices of adiposity. These data suggest that the postural element of SB (sitting) is not sufficient for the accumulation of adiposity, rather activities requiring low EE (<1.5 METs) and the absence of MVPA, regardless of posture, are associated with higher fat mass.

A Low Energy–Dense Diet in the Context of a Weight-Management Program Affects Appetite Control in Overweight and Obese Women

Abstract Background Low energy–dense (LED) foods reduce energy intake (EI); whether this effect is sustained over time and during weight loss is unknown. Objective This trial examined the effects of LED compared with high energy–dense (HED) meals on appetite, EI, and control over eating in the laboratory and during a weight-management program that encourages unrestricted intake of LED foods [Slimming World, UK (SW)] compared with a self-led Standard Care program [NHS weight-loss plan (SC)]. Methods Overweight and obese women [n = 96; mean ± SD age: 41.03 ± 12.61 y; mean ± SD body mass index (in kg/m2): 34.00 ± 3.61] were recruited from the SW or SC programs. Primary outcomes included appetite, food preferences (liking and wanting for LED and HED foods), cravings, and evening meal EI (LED, HED) in response to calorie-matched LED (≤0.8 kcal/g) and HED (≥2.5 kcal/g) breakfast and lunch meals. Probe-day tests were conducted at weeks 3 and 4 and repeated at weeks 12 and 13 in a within-day crossover design. Secondary outcomes, including body weight and program experience, were measured from weeks 1 to 14 in a parallel-group design. Dietary compliance was monitored with the use of weighed food diaries at weeks 3 and 12. Results Intention-to-treat (ITT) and completers analyses showed that the SW group lost more weight than the SC group [ITT: −5.9% (95% CI: −4.7%, –7.2%) compared with −3.5% (−2.3%, −4.8%), P < 0.05; completers: −6.2% (−4.8%, −7.6%) compared with 3.9% (−2.5%, −5.2%), P < 0.05]. The SW group reported greater control over eating and more motivation to continue the program compared with the SC group. LED meals increased sensations of fullness and reduced hunger on probe days (P < 0.001). Total-day EI was 1057 ± 73 kcal less (95% CI: 912, 1203 kcal; 36%) under LED compared with HED conditions (P < .001). Liking for LED and HED foods and wanting for HED foods were lower before lunch under LED compared with HED conditions, and liking decreased to a greater extent after the LED lunch. The SW group reported fewer cravings under LED compared with HED conditions (P < 0.05). On probe days, appetite and EI outcomes did not differ between weeks 3 and 12 or between the SW and SC groups. Conclusion LED meals improve appetite control in women attempting weight loss and the effect is sustainable. Consumption of LED meals likely contributed to weight loss in the SW program. This study was registered at clinicaltrials.gov as NCT02012426.

Priming food intake with weight control cues: Systematic review with a meta-analysis

BackgroundA growing number of studies suggest that exposure to cues which are associated with weight control can prime or prompt controlled food intake in tempting food environments. However, findings are mixed and understanding which types of cues and for whom such cues may be most effective is needed to inform subsequent research and societal applications. A systematic review and meta-analysis were conducted to evaluate the effects of exposure to weight control cues compared with control cues on food intake.MethodsPsycINFO, Medline, Embase and Web of Science were searched using key terms. Hedge’s g was used to calculate effect sizes based on mean food intake, standard deviations and sample sizes extracted from relevant publications and, a random effects model was used for the meta-analysis.ResultsTwenty-five articles consisting of 26 studies were eligible. Data from 25 studies (31 effect sizes) were available for the meta-analysis. Overall, weight control cues reduced food intake, albeit to a trivial effect (ES: -0.149, 95% CI: -0.271 to − 0.027). Subgroup analyses when studies which induced negative affect were removed showed that for individuals with strong weight control goals the effect was small-to-moderate (ES: -0.440, 95% CI: -0.718 to − 0.163), whereas for individuals with weak weight control goals this effect was trivial and non-significant (ES: 0.014, 95% CI: -0.249 to 0.278). Cue type and level of engagement did not significantly moderate the effect; however, specific cues (low-calorie foods and thin models) and attended engagement yielded significant effects. Caution is needed interpreting these findings as most studies were rated with high risk of bias and a number of studies could not be included in the subgroup analyses.ConclusionsBased on the data available, weight control cues reduce food intake in individuals with strong weight control goals. Further research is needed to explore longer term effects of cue exposure and confirm underlying mechanisms. PROSPERO registry#CRD42016052396.

Identifying the psychological, nutrient and sensory attributes of foods used for weight management in dieting and non-dieting consumers

The global dimensions of foods determining consumer perception of successful weight management are unclear, but of considerable academic and commercial interest. It is also unknown whether these attributes are given greater or lesser importance in dieters compared to non-dieters. The current study examined 75 commercially available foods according to perceived and/or actual sensory (e.g. taste), psychological (e.g. how filling, pleasantness) and nutritional (e.g. macronutrient) dimensions and their association with perceived successful weight management. In total 716 dieting (n = 279) and non-dieting (n = 437) consumers were recruited. Perceptual data were collected using 3 online questionnaires while objective nutritional data were gathered from manufacturer packaging or nutrition databases. Linear modelling for perceived food dimensions revealed that energy content and how filling were the most important predictors of perceived weight management in the total sample (p < 0.0001;R2 = 0.95) and among non-dieters (p < 0.0001;R2 = 0.95). However in dieters, an additional hedonic component was significant in the model with perceived pleasantness positively (β = 0.22; p < .001), and eating-from-desire negatively (β = −.27; p < .001) associated with weight management. Analyses of actual food dimensions did not differ according to dietingstatus. In the total sample, %protein (r = .27; p < 0.05) and %fat (r = −.43; p < 0.001) correlated with perceived weight management, but made no contribution to linear models when energy content was included. Psychological and nutritional dimensions of foods are important determinants of their perceived value for successful weight management; with energy content and how filling as the most important dimensions. The perceived attributes of food associated with successful weight management differ between dieters and non-dieters, with higher pleasantness and lower eatingfrom-desire as characteristics in dieters only.