Trial reportThe international journal of behavioral nutrition and physical activity2020
Reductions to main meal portion sizes reduce daily energy intake regardless of perceived normality of portion size: a 5 day cross-over laboratory experiment.
Trial report in The international journal of behavioral nutrition and physical activity, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT03811210 (Using the Norm Range to Predict the Effect of Food Portion Size Reductions on Compensation), which is not on this map. Cited by 13 papers, 5 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Using the Norm Range to Predict the Effect of Food Portion Size Reductions on Compensation
Who cites it
13 citing papers in PubMed, 5 syntheses or guidelines pooled it, 33 citations in OpenAlex.
- Eating while distracted: a systematic review and meta-analysis of the effect of distraction on concurrent and later energy intake in adults.The American journal of clinical nutrition · 2026Pooled it
- Temporal Eating Patterns and Colorectal Cancer: A Systematic Review.Current nutrition reports · 2025Pooled it
- A systematic review of the relationship between portion size and indexes of adiposity in children.Obesity reviews : an official journal of the International Association for the Study of Obesity · 2025Pooled it
- Downsizing food: a systematic review and meta-analysis examining the effect of reducing served food portion sizes on daily energy intake and body weight.The British journal of nutrition · 2023Pooled it
- Systematic Review and Meta-Analysis on the Effect of Portion Size and Ingestive Frequency on Energy Intake and Body Weight among Adults in Randomized Controlled Feeding Trials.Advances in nutrition (Bethesda, Md.) · 2022Pooled it
- Socioeconomic position and the influence of food portion size on daily energy intake in adult females: two randomized controlled trials.The international journal of behavioral nutrition and physical activity · 2023Trial
- Impact of decreasing the proportion of higher energy foods and reducing portion sizes on food purchased in worksite cafeterias: A stepped-wedge randomised controlled trial.PLoS medicine · 2021Trial
- Portion Estimation, Satiety Perception and Energy Intake Following Different Breakfast Portion Sizes in Healthy Adults.Nutrition bulletin · 2025Article
- Differences between the normal and perceived appropriate portion sizes of discretionary foods.European journal of clinical nutrition · 2025Article
- Energy Imbalance Gap, Anthropometric Measures, Lifestyle, and Sociodemographic Correlates in Latin American Adults-Results from the ELANS Study.International journal of environmental research and public health · 2022Article
- The Economics of a "portion size reduction" policy.PloS one · 2022Article
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Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors at 3 institutions in 2 countries.
Funding
Abstract
backgroundSmaller portions may help to reduce energy intake. However, there may be a limit to the magnitude of the portion size reduction that can be made before consumers respond by increasing intake of other food immediately or at later meals. We tested the theoretical prediction that reductions to portion size would result in a significant reduction to daily energy intake when the resulting portion was visually perceived as 'normal' in size, but that a reduction resulting in a 'smaller than normal' portion size would cause immediate or later additional eating.
methodsOver three 5-day periods, daily energy intake was measured in a controlled laboratory study using a randomized crossover design (N = 30). The served portion size of the main meal component of lunch and dinner was manipulated in three conditions: 'large-normal' (747 kcal), 'small-normal' (543 kcal), and 'smaller than normal' (339 kcal). Perceived 'normality' of portion sizes was determined by two pilot studies. Ad libitum daily energy intake from all meals and snacks was measured.
resultsDaily energy intake in the 'large-normal' condition was 2543 kcals. Daily energy intake was significantly lower in the 'small-normal' portion size condition (mean difference - 95 kcal/d, 95% CI [- 184, - 6], p = .04); and was also significantly lower in the 'smaller than normal' than the 'small-normal' condition (mean difference - 210 kcal/d, 95% CI [- 309, - 111], p < .001). Contrary to predictions, there was no evidence that the degree of additional food consumption observed was greater when portions were reduced past the point of appearing normal in size.
conclusionsReductions to the portion size of main-meal foods resulted in significant decreases in daily energy intake. Additional food consumption did not offset this effect, even when portions were reduced to the point that they were no longer perceived as being normal in size.
trial registrationProspectively registered protocol and analysis plan: https://osf.io/natws/; retrospectively registered: https://clinicaltrials.gov/ct2/show/NCT03811210.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.