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

Individual differences in sensory and expectation driven interoceptive processes: a novel paradigm with implications for alexithymia, disordered eating and obesity

Those with disordered eating and/or obesity often express difficulties in sensing or interpreting what is happening in the body (interoception). However, research is hindered by conceptual confusion, concerns surrounding domain specificity, and an inability to distinguish sensory (bottom-up) and expectation driven (top-down) interoceptive processes. A paradigm was therefore developed from an active inference perspective. Novel indices were computed and examined in those with alexithymia: a personality associated with interoceptive deficits and disordered eating. The paradigm successfully identified individuals driven by sensations rather than expectations: alexithymia was characterized by attenuated prior precision (a larger divergence between pre-prandial and post-prandial satiety, and low expectation confidence), and increased prediction error (a higher correlation between changes in hunger and blood glucose, and greater rebound hunger after a sensory incongruent drink). In addition, those with a higher BMI were less confident and had a larger anticipated satiety divergence. These findings demonstrate the need to move beyond existing paradigms such as the Satiety Quotient and Heartbeat Counting Task which may have limited our understanding of eating behaviour.

Dietary energy density and appetite: A systematic review and meta-analysis of clinical trials

Studies have suggested that dietary energy density (DED) may affect weight gain by altering appetite. Although many studies have investigated the effect of DED on appetite, findings are inconsistent and, to our knowledge, there are no systematic reviews and meta-analyses on this topic. Therefore, the aim of this systematic review and meta-analysis was to summarize the effect of DED on appetite. The current meta-analysis revealed changing the DED had no significant effect on hunger but increased fullness. More high-quality randomized controlled trials are needed to investigate the effects of DED on appetite components. We searched titles, abstracts, and keywords of articles indexed in ScienceDirect, MEDLINE, and Google Scholar databases up to July 2018 to identify eligible RCT studies. Random effects model was used to estimate the pooled effect of DED on appetite. Among the 21 studies identified in the systematic literature search, 11 reports were included in the meta-analysis. Based on the Cochrane Collaboration Risk of Bias tool, 6 studies were considered as good quality, two were fair, and three studies were poor. The mean ± standard deviation for energy density, in studies which assessed fullness, was 1.65 ± 1 in high energy dense (HED) diet and 0.93 ± 0.93 in low energy dense (LED) diet. The corresponding values for hunger were 1.67 ± 0.69 and 0.70 ± 0.32, respectively. Compared with a LED diet, consumption of HED increased fullness (weighed mean difference [WMD] 2.95 mm; 95% CI 0.07-5.82, P = 0.044, I² 98.1%) but had no significant effect on hunger (WMD 1.31 mm; 95% CI -7.20 to 9.82, P = 0.763, I² 99.1%). The current meta-analysis revealed changing the DED had no significant effect on hunger but increased fullness. More high-quality RCTs are needed to investigate the effects of DED on appetite components.

Americans' Perceptions about Fast Food and How They Associate with Its Consumption and Obesity Risk

We aimed to systematically examine Americans' perceptions of fast food (FF) and how these perceptions might affect fast food consumption (FFC) and obesity risk. We searched PubMed and Google for studies published in English until February 17, 2017 that reported on Americans' perceptions (defined as their beliefs, attitudes, and knowledge) regarding FF as well as those on their associations with FFC and obesity risk. Thirteen articles met inclusion criteria. Limited research has been conducted on these topics, and most studies were based on convenience samples. A 2013 nationally representative phone survey of about 2000 subjects showed that one-fifth of Americans thought FF was good for health, whereas two-thirds considered FF not good. Even over two-thirds of weekly FF consumers (47% of the total population) thought FF not good. Americans seem to have limited knowledge of calories in FF. Negative and positive FF perceptions were associated with FFC. Those who consumed less FF seemed more likely to view FF negatively. When Americans valued the convenience and taste of FF and preferred FF restaurants with kid's menus and play areas, they were likely to purchase more FF. Available research indicates neither perceived availability of FF nor Geographical Information System (GIS)-based FF presence in the neighborhood has significant associations with weekly FFC. No studies examined potential links between FF perceptions and obesity risk. Americans' perceptions of FF and how they might associate with FFC and obesity risk are understudied. Considerable variation was observed in Americans' perceptions and FFC.

The effect of preload/meal energy density on energy intake in a subsequent meal: A systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis of the effects of preload/meal energy density on energy intake in a subsequent meal(s).

METHODS

Multiple databases were searched for studies published through December 2016 on the effects of preload/meal energy density on energy intake in a subsequent meal(s). We extracted information on mean energy intake in a subsequent meal(s) and on variables that could contribute to between-subject heterogeneity.

RESULTS

Forty and Thirty nine eligible studies were identified for our systematic review and meta-analysis, respectively. The meta-analysis showed that preload/meal energy density did not affect energy intake in a subsequent meal(s) (95% CI:-21.21, 21.29). As heterogeneity was remarkable among studies, we stratified the studies by intervention type into "meal" or "preload" classifications. In the "preload" subgroup, studies used either fixed energy or fixed weight preloads. The results reveal that in comparison to a high energy-dense (HED) preload, consuming a low energy-dense (LED) preload with same weight resulted in higher energy intake in a subsequent meal (95% CI: 9.72, 56.19). On the other hand, decreased energy intake was observed after consuming an LED preload compared to after consumption of an HED preload with same energy content (95% CI: -138.71, -57.33). In the "meal" subgroup, studies were categorized by different subsequent meal (i.e., "afternoon or evening", "lunch" and "dinner or post-dinner"). Meta-analysis showed that an LED meal resulted in more energy intake only in afternoon or evening meals (95% CI: 14.82, 31.22).

CONCLUSION

In summary, the current analysis revealed that we can restrict the energy intake by consuming an LED preload. Moreover, consuming an LED preload could favorably affect preload+meal energy intake.

Food Choice and Nutrition: A Social Psychological Perspective

In this Special Issue, entitled "Food choice and Nutrition: A Social Psychological Perspective", three broad themes have been identified: (1) social and environmental influences on food choice; (2) psychological influences on eating behaviour; and (3) eating behaviour profiling.The studies that addressed the social and environmental influences indicated that further research would do well to promote positive food choices rather than reduce negative food choices; promote the reading and interpretation of food labels and find ways to effectively market healthy food choices through accessibility, availability and presentation. The studies on psychological influences found that intentions, perceived behavioural control, and confidence were predictors of healthy eating. Given the importance of psychological factors, such as perceived behavioural control and self-efficacy, healthy eating interventions should reduce barriers to healthy eating and foster perceptions of confidence to consume a healthy diet. The final theme focused on the clustering of individuals according to eating behaviour. Some "types" of individuals reported more frequent consumption of fast foods, ready meals or convenience meals or greater levels of disinhibitiona nd less control over food cravings. Intervention designs which make use of multi-level strategies as advocated by the Ecological Model of Behaviour change that proposes multi-level (combining psychological, social and environmental) strategies are likely to be more effective in reaching and engaging individuals susceptible to unhealthy eating habits than interventions operating on a single level.