Quantifying consumer portion control practices. A cross-sectional study

Highlights

• A survey of portion control practices was conducted among 1012 consumers.

• Measurement, eating and purchasing strategies were identified by factor analysis.

• Having a higher general health interest was associated with greater strategy use.

• Being female was associated with greater strategy use.

• Greater eating and purchasing -strategy use was associated with smaller pizza size.

Abstract

The use of portion control practices has rarely been quantified. The present study aimed to: (1) explore which portion control practices are actually used by the general population and their association with cognitive restraint, demographic background and general health interest (GHI), and (2) examine how the usage of portion control practices predicts the estimated consumption of an energy dense food (i.e. pizza). Twenty-two portion control practices were rated in terms of their frequency of use from ‘never’ to ‘very often’ by a representative sample of 1012 consumers from the island of Ireland. Three factors were extracted and named: measurement-strategy scale, eating-strategy scale, and purchasing-strategy scale. The eating-strategy scale score was the highest, while the measurement-strategy scale carried the lowest frequency score. For each strategy scale score, the strongest predictor was GHI, followed by gender. Having higher GHI and being female were independently associated with more frequent portion control. Both the eating-strategy scale score and the purchasing-strategy scale score were negatively associated with pizza portion size consumption estimates. In conclusion, while this study demonstrates that the reported use of portion control practices is low, the findings provide preliminary evidence for their validity. Further studies are needed to explore how portion control practices are used in different kinds of portion size decisions and what their contribution is to the intake of food over an extended period of time.

Introduction

Larger portion sizes have been frequently cited as a key driver of excess energy intake and weight gain (Duffey, Popkin, 2011, Ledikwe et al, 2005). As such, some industry, healthcare professional and non-governmental organisations have attempted to raise consumer awareness of reference serving sizes (Mayfield-Blake, 2012, Poelman et al, 2013, Safefood,, Tesco,) and encourage appropriate portion size selection and consumption by giving advice on various portion control practices which can be used by consumers in different settings (Mayfield-Blake, 2012, Safefood,, Steenhuis, Vermeer, 2009). In the context of in-home eating, such practices may include using smaller bowls or plates for meals, reducing the convenience of stockpiled food or plating smaller dinner portions in advance, whereas in a restaurant setting, practices might include ordering reduced sized portions, and sharing food (Mayfield-Blake, 2012, Safefood,, Steenhuis, Vermeer, 2009). Although these portion control practices have been proposed in the literature (Steenhuis & Vermeer, 2009) and are currently being promoted by advocates of healthy eating (Mayfield-Blake, 2012, Safefood,), their frequency of use has rarely been measured.

The construct of portion control has been broadly studied before (Aina Mardiah et al, 2012, Nothwehr et al, 2013, Nothwehr et al, 2007, Nothwehr, Peterson, 2005, Poelman et al, 2014). However, the measures employed are generally limited in scope and mostly relate to the concept rather than to the practices which can be employed to control the amount of food eaten at any one time as either a meal or snack. Of note, a recent study (Poelman et al., 2014) explored a mix of practices which could be viewed as both generalised (e.g. “Control your daily amount by limiting your intake to the main meals and restricting the amount you eat in between) and practical (e.g. “Do not snack on ingredients”) suggestions to limit the amount of food consumed overall. However, to the best of our knowledge, no studies have yet developed a scale which measures the use of portion control practices in different settings to specifically reduce food portion size i.e. the amount of food intended to be consumed by an individual in a single eating occasion.

More detailed assessments of portion control are merited for several reasons. Firstly, it is desirable to have a measure of practices related to food portion control, as opposed to a general intent to limit and monitor overall food intake. Secondly, it is important to understand exactly what, if any, portion control practices are being used by consumers. If these are evaluated in intervention and cross-sectional studies in the future, it may not only reveal which, if any, type of portion control practices are acceptable and effective in helping consumers to manage portion size selection and consumption, but it may also provide valuable insights into key determinants of portion control practice use. This should ultimately inform nutrition education stakeholders about the best means of improving the efficiency and effectiveness of their portion size intervention initiatives.

The aim of the present paper is twofold: first to explore which portion control practices are actually used by the general population and their association with cognitive restraint, demographic background and general health interest (GHI), and second, to examine how the usage of portion control practices predicts the estimated consumption of an energy dense food (i.e. pizza) which is commonly consumed on the island of Ireland. In light of previous research suggesting that women are more interested in health-related behaviours than men (Provencher et al, 2003, Steptoe, Wardle, 1992, Wardle, Steptoe, 1991), we expected that females would use more portion control practices than males. Furthermore, given the previously reported positive relationship between GHI and healthful food choices (Roininen et al., 2001), we also expected that participants who were more health oriented would score higher on portion control strategy use.