Does measuring body weight impact subsequent response to eating behavior questions?

OBJECTIVES: If being weighed impacts perceptions of eating behavior, it is important that the order of questionnaires and weighing be considered in research and practice. A quasi-experimental study was performed to examine whether being weighed immediately prior to completing a questionnaire affects responses to eating behavior questions. It was hypothesized that being weighed would serve as a priming stimulus and increase measures of dietary restraint, disinhibition, and hunger. METHODS: Trained researchers collected a sample of volunteers (n = 355) in 8 locations in the United States on two Saturdays in the summer of 2011. Half of the participants were weighed immediately prior to completing the Three Factor Eating Questionnaire (TFEQ), with the remaining half weighed immediately after TFEQ completion. RESULTS: A priori hypotheses were not supported despite replicating known relationships between weight, dietary restraint and disinhibition. Results indicated that being weighed first produced a difference in differences on disinhibition scores between low restraint score (95% CI = 4.65-6.02) and high restraint score (95% CI = 6.11-7.57) compared to being weighed after questionnaire completion (p = 0.003). However, this relationship was not significant when modeling restraint as a continuous variable, questioning the use of dichotomization. CONCLUSIONS: Being weighed is unlikely to be a strong enough prime to significantly change scores on eating behavior questionnaires for everyone, but may allow differences in restraint status to become more evident. Researchers assessing dietary restraint should be wary of the possibility of producing different results when treating restraint as continuous or dichotomous, which could lead to different interpretations.

The Effects of Increased Protein Intake on Fullness: A Meta-Analysis and Its Limitations.

BACKGROUND: Higher protein intake has been implicated in weight management because of its appetitive properties. However, the effects of protein intake on appetitive sensations such as fullness have not been systematically assessed. Meta-analysis is a useful technique to evaluate evidence of an intervention's effect on testable outcomes, but it also has important limitations. OBJECTIVE: The primary aim of this study was to synthesize the available evidence on the effect of protein intake on fullness using a quantitative meta-analysis and a secondary directional analysis using the vote-counting procedure. A tertiary aim was to address limitations of meta-analyses as they pertain to findings from this meta-analysis. DESIGN: We searched multiple databases for interventional studies that evaluated the effect of increased protein intake on fullness ratings. Inclusion criteria for both analyses were as follows: healthy human participants, preload studies that utilized intact dietary protein, delivery of protein load orally, and studies reporting fullness as an outcome. For the meta-analysis, an additional criterion was that the studies also needed to report 2- to 4-hour area under the curve value for fullness. RESULTS: Five studies met all criteria for the meta-analysis. Twenty-eight studies met all criteria for the directional analysis. The meta-analysis indicated higher protein preloads have a greater effect on fullness than lower protein preloads (overall effect estimate: 2,435.74 mm.240 min, (95% CI 1,375.18 to 3,496.31 mm.240 min; P<0.0001). The directional analysis also revealed a positive effect on fullness with higher protein preloads (P<0.01). Many related scientifically rigorous studies were excluded from the analysis because analytical criteria required a narrowly focused research question. CONCLUSIONS: The present analyses show that higher protein preloads increase fullness ratings more than lower protein preloads under tightly defined conditions. Extrapolation of findings to common conditions outside the specified criteria of this analysis must be made cautiously, as must speculation about the influence of fullness sensations on ingestive behavior, body weight, and various health outcomes.

Anticipatory and reactive responses to chocolate restriction in frequent chocolate consumers.

OBJECTIVE: Many individuals have difficulty adhering to a weight loss diet. One possible explanation could be that dietary restriction paradoxically contributes to overconsumption. The objective of this study was to examine ingestive behavior under a forced chocolate restriction with a focus on the anticipatory restriction period and the post-restriction period in frequent chocolate consumers. METHODS: Fifty-six male (N = 18) and female (N = 38) high chocolate consumers with high (N = 25) or low (N = 31) cognitive disinhibition participated. Chocolate snacks were provided for a week each to establish baseline, pre-restriction, and post-restriction consumption, Chocolate snacks were replaced with nonchocolate snacks during a 3-week chocolate restriction period. RESULTS: Highly disinhibited participants felt more guilty and consumed significantly more energy than low disinhibited participants across snack conditions. Low disinhibited participants consumed significantly less in the post-restriction period compared to baseline and the pre-restriction period, while high disinhibited participants consumed the same amount across all conditions. Aggregating the data, high and low disinhibited chocolate consumers ate snacks more frequently in the pre- and post-restriction periods compared to the baseline period. CONCLUSIONS: This study suggests that for some individuals, restriction of a preferred food like chocolate may be contraindicated for energy restriction and weight management.