Individual differences and moderating participant characteristics in the effect of reducing portion size on meal energy intake: Pooled analysis of three randomized controlled trials

Socioeconomic position and the influence of food portion size on daily energy intake in adult females: two randomized controlled trials

BACKGROUND

Reducing portion sizes of commercially available foods could be an effective public health strategy to reduce population energy intake, but recent research suggests that the effect portion size has on energy intake may differ based on socioeconomic position (SEP).

OBJECTIVE

We tested whether the effect of reducing food portion sizes on daily energy intake differed based on SEP.

METHODS

Participants were served either smaller or larger portions of food at lunch and evening meals (N = 50; Study 1) and breakfast, lunch and evening meals (N = 46; Study 2) in the laboratory on two separate days, in repeated-measures designs. The primary outcome was total daily energy intake (kcal). Participant recruitment was stratified by primary indicators of SEP; highest educational qualification (Study 1) and subjective social status (Study 2), and randomisation to the order portion sizes were served was stratified by SEP. Secondary indicators of SEP in both studies included household income, self-reported childhood financial hardship and a measure accounting for total years in education.

RESULTS

In both studies, smaller (vs larger) meal portions led to a reduction in daily energy intake (ps < .02). Smaller portions resulted in a reduction of 235 kcal per day (95% CI: 134, 336) in Study 1 and 143 kcal per day (95% CI: 24, 263) in Study 2. There was no evidence in either study that effects of portion size on energy intake differed by SEP. Results were consistent when examining effects on portion-manipulated meal (as opposed to daily) energy intake.

CONCLUSIONS

Reducing meal portion sizes could be an effective way to reduce overall daily energy intake and contrary to other suggestions it may be a socioeconomically equitable approach to improving diet.

TRIAL REGISTRATION

These trials were registered at www.

CLINICALTRIALS

gov as NCT05173376 and NCT05399836.

Downsizing food: a systematic review and meta-analysis examining the effect of reducing served food portion sizes on daily energy intake and body weight

Portion sizes of many foods have increased over time. However, the size of effect that reducing food portion sizes has on daily energy intake and body weight is less clear. We used a systematic review methodology to identify eligible articles that used an experimental design to manipulate portion size served to human participants and measured energy intake for a minimum of 1 d. Searches were conducted in September 2020 and again in October 2021. Fourteen eligible studies contributing eighty-five effects were included in the primary meta-analysis. There was a moderate-to-large reduction in daily energy intake when comparing smaller v. larger portions (Standardised Mean Difference (SMD) = -0·709 (95 % CI: -0·956, -0·461), approximately 235 kcal (983·24 kJ)). Larger reductions to portion size resulted in larger decreases in daily energy intake. There was evidence of a curvilinear relationship between portion size and daily energy intake; reductions to daily energy intake were markedly smaller when reducing portion size from very large portions. In a subset of studies that measured body weight (four studies contributing five comparisons), being served smaller v. larger portions was associated with less weight gain (0·58 kg). Reducing food portion sizes may be an effective population-level strategy to prevent weight gain.

Switching between bites of food and sips of water is related to food intake across meals varying in portion size

Individuals eat more when served more food, but little is known about how this portion size effect is moderated by meal-related characteristics, particularly the inclusion of water served as a beverage. Patterns of eating and drinking as well as consumption of water could affect satiation by modifying exposure to the sensory qualities of food. In a crossover design, 44 adults ate lunch in the laboratory once a week for 4 weeks and intake was measured. The meal was a pasta dish that was varied in portion size (400, 500, 600, or 700 g) plus 700 g of water. Meals were video-recorded to count bites and sips and the number of switches between them. Sensory-specific satiety (SSS) was evaluated as the relative decline in hedonic ratings of the pasta after consumption. Serving larger portions led to a curvilinear increase in food intake (p < 0.0001). Neither switching between bites and sips nor water intake moderated the portion size effect. Independent of portion served, across all meals switching more frequently was related to greater food consumption (5.7 ± 1.8 g more food consumed for each additional switch, p = 0.004). Greater water intake was also related to greater food intake across portions (1.1 ± 0.5 g more food consumed for each additional 10 g of water, p = 0.025), but this effect was not significant after accounting for switching (p = 0.38). The magnitude of SSS was unaffected by switching, suggesting that switching allowed greater food intake for a given hedonic decline. At a meal with a single food, intake was greater when larger portions were served and also when there was more switching between bites and sips. Switching between food and water may promote energy intake by attenuating the development of SSS.

Do eating behavior traits predict energy intake and body mass index? A systematic review and meta-analysis

At present, it is unclear whether eating behavior traits (EBT) predict objectively measured short-term energy intake (EI) and longer-term energy balance as estimated by body mass index (BMI). This systematic review examined the impact of EBT on BMI and laboratory-based measures of EI in adults ( ≥ 18 years) in any BMI category, excluding self-report measures of EI. Articles were searched up until 28th October 2021 using MEDLINE, PsycINFO, EMBASE and Web of Science. Sixteen EBT were identified and the association between 10 EBT, EI and BMI were assessed using a random-effects meta-analysis. Other EBT outcomes were synthesized qualitatively. Risk of bias was assessed with the mixed methods appraisal tool. A total of 83 studies were included (mean BMI = 25.20 kg/m² , mean age = 27 years and mean sample size = 70). Study quality was rated moderately high overall, with some concerns in sampling strategy and statistical analyses. Susceptibility to hunger (n = 6) and binge eating (n = 7) were the strongest predictors of EI. Disinhibition (n = 8) was the strongest predictor of BMI. Overall, EBT may be useful as phenotypic markers of susceptibility to overconsume or develop obesity (PROSPERO: CRD42021288694).

Eating rate and bite size were related to food intake across meals varying in portion size: A randomized crossover trial in adults

Serving larger portions leads to increased food intake, but behavioral factors that influence the magnitude of this portion size effect have not been well characterized. We investigated whether measures of eating microstructure such as eating rate and bite size moderated the portion size effect. We also explored how sensory-specific satiety (SSS; the relative hedonic decline of a food as it is eaten) was affected by eating microstructure and larger portions. In a randomized crossover design, 44 adults aged 18-68 y (66% women; 46% with overweight and obesity) ate lunch in the laboratory once a week for 4 weeks. The meal consisted of pasta that was varied in portion size (400, 500, 600, or 700 g) and 700 g of water. Meals were video-recorded to assess bite count and meal duration, which were used to calculate mean eating rate (g/min) and mean bite size (g/bite). At each meal participants also completed an assessment of SSS. The results showed that as larger portions were served, meal intake increased in a curvilinear manner (p < 0.0001). Measures of eating microstructure did not moderate the portion size effect but were related to intake across all portions; faster eating rate, larger bite size, higher bite count, and longer meal duration were associated with greater consumption at all meals (all p < 0.0001). SSS was not influenced by any measure of eating microstructure or by portion size (all p > 0.10). In summary, the portion size effect was not moderated by eating microstructure, but relatively faster eating rates and larger bite sizes at meals, along with large portions, combined to increase food intake.

Front-of-pack (FOP) labelling systems to improve the quality of nutrition information to prevent obesity: NutrInform Battery vs Nutri-Score

Many systems for classifying food products to adequately predict lower all-cause morbidity and mortality have been proposed as front-of-pack (FOP) nutritional labels. Although the efforts and advances that these systems represent for public health must be appreciated, as scientists involved in nutrition research and belonging to diverse Italian nutrition scientific societies, we would like to draw stakeholders' attention to the fact that some FOP labels risk being not correctly informative to consumers' awareness of nutritional food quality. The European Commission has explicitly called for such a nutrition information system to be part of the European "strategy on nutrition, overweight and obesity-related issues" to "facilitate consumer understanding of the contribution or importance of the food to the energy and nutrient content of a diet". Some European countries have adopted the popular French proposal Nutri-Score. However, many critical limits and inadequacies have been identified in this system. As an alternative, we endorse a new enriched informative label-the NutrInform Battery-promoted by the Italian Ministry of Health and deeply studied by the Center for Study and Research on Obesity, Milan University. Therefore, the present position paper limits comparing these two FOP nutritional labels, focusing on the evidence suggesting that the NutrInform Battery can help consumers better than the Nutri-Score system to understand nutritional information, potentially improving dietary choices. LEVEL OF EVIDENCE: II. Evidence was obtained from well-designed controlled trials without randomization.

Evolution of food intake estimates in Brazil: the 2008-2009 and 2017-2018 National Dietary Surveys

ABSTRACT Objective To present changes in the estimated amount of food intake in Brazil between the 2008-2009 and 2017-2018 National Dietary Surveys. Methods Food intake data from the 2008-2009 and 2017-2018 surveys were used to highlight the differences in the frequencies of foods mentioned, the number of the measurement units mentioned, and the frequency of measurements that were incompatible with the reported food and were exchanged by the most mentioned measurement (standard measurement), as well as to describe the updates performed in the database between edits. Results The elaboration of the 2017-2018 referenced measurement table was based on the 2008-2009 table, which was revised and updated. In the 2008-2009 survey, 9980 household measurements were mentioned for 1970 types of food and preparations, while in 2017-2018 there were 11050 and 2534, respectively. While in 2008-2009, 2.8% of citations were replaced by the standard measurement, in 2017-2018, only 0.7% of food items needed to be replaced. Conclusion The procedures used to estimate the amount of food intake between the surveys allowed updating the table of household measurements and minimizing errors in the estimate of this amount, with a reduction in measurement units that were inconsistent or incompatible with the aforementioned foods.

Impact of Portion Control Tools on Portion Size Awareness, Choice and Intake: Systematic Review and Meta-Analysis

Portion control utensils and reduced size tableware amongst other tools, have the potential to guide portion size intake but their effectiveness remains controversial. This review evaluated the breadth and effectiveness of existing portion control tools on learning/awareness of appropriate portion sizes (PS), PS choice, and PS consumption. Additional outcomes were energy intake and weight loss. Published records between 2006–2020 (n = 1241) were identified from PubMed and WoS, and 36 publications comparing the impact of portion control tools on awareness (n = 7 studies), selection/choice (n = 14), intake plus related measures (n = 21) and weight status (n = 9) were analyzed. Non-tableware tools included cooking utensils, educational aids and computerized applications. Tableware included mostly reduced-size and portion control/calibrated crockery/cutlery. Overall, 55% of studies reported a significant impact of using a tool (typically smaller bowl, fork or glass; or calibrated plate). A meta-analysis of 28 articles confirmed an overall effect of tool on food intake (d = –0.22; 95%CI: –0.38, –0.06; 21 comparisons), mostly driven by combinations of reduced-size bowls and spoons decreasing serving sizes (d = –0.48; 95%CI: –0.72, –0.24; 8 comparisons) and consumed amounts/energy (d = –0.22; 95%CI: –0.39, –0.05, 9 comparisons), but not by reduced-size plates (d = –0.03; 95%CI: –0.12, 0.06, 7 comparisons). Portion control tools marginally induced weight loss (d = –0.20; 95%CI: –0.37, –0.03; 9 comparisons), especially driven by calibrated tableware. No impact was detected on PS awareness; however, few studies quantified this outcome. Specific portion control tools may be helpful as potentially effective instruments for inclusion as part of weight loss interventions. Reduced size plates per se may not be as effective as previously suggested.