Energy compensation in the real world: Good compensation for small portions of chocolate and biscuits over short time periods in complicit consumers using commercially available foods

Highlights

• Studies using covert food manipulations tend to demonstrate poor energy compensation.

• We studied responses to chocolate, biscuits and fruit bars using overt manipulations.

• We demonstrate good compensation for familiar food portions over short time periods.

• Studies using covert manipulations may have limited transfer to real world scenarios.

Abstract

While investigations using covert food manipulations tend to suggest that individuals are poor at adjusting for previous energy intake, in the real world adults rarely consume foods of which they are ill-informed. This study investigated the impact in fully complicit consumers of consuming commercially available dark chocolate, milk chocolate, sweet biscuits and fruit bars on subsequent appetite. Using a repeated measures design, participants received four small portions (4 × 10–11 g) of either dark chocolate, milk chocolate, sweet biscuits, fruit bars or no food throughout five separate study days (counterbalanced in order), and test meal intake, hunger, liking and acceptability were measured. Participants consumed significantly less at lunch following dark chocolate, milk chocolate and sweet biscuits compared to no food (smallest t(19) = 2.47, p = 0.02), demonstrating very good energy compensation (269–334%). No effects were found for fruit bars (t(19) = 1.76, p = 0.09), in evening meal intakes (F(4,72) = 0.62, p = 0.65) or in total intake (lunch + evening meal + food portions) (F(4,72) = 0.40, p = 0.69). No differences between conditions were found in measures of hunger (largest F(4,76) = 1.26, p = 0.29), but fruit bars were significantly less familiar than all other foods (smallest t(19) = 3.14, p = 0.01). These findings demonstrate good compensation over the short term for small portions of familiar foods in complicit consumers. Findings are most plausibly explained as a result of participant awareness and cognitions, although the nature of these cognitions cannot be discerned from this study. These findings however, also suggest that covert manipulations may have limited transfer to real world scenarios.

Introduction

Appetite is commonly investigated using covert manipulations, with the deliberate intention that participants remain as unaware as possible of any differences between different manipulations (e.g. Almiron-Roig et al, 2013, Blundell et al, 2010). While clearly valuable and necessary for the investigation of physiological effects (Blundell et al., 2010), consumers in the real world do not only consume in response to their physiology (Blundell et al., 2010), and are rarely faced with foods about which they know nothing, or about which the information they have might be grossly incorrect.

Studies using covert manipulations of energy content typically demonstrate poor adjustment for previous energy intake at subsequent time points (see Almiron-Roig et al, 2013, Blundell et al, 2010). Limited studies, however, also demonstrate better compensation where consumers are informed of the foods they are consuming (overt manipulations) compared to uninformed (Roberto et al, 2010, Shide, Rolls, 1995).

Using foods with which they are familiar, individuals in the real world thus may be more able to adjust their energy intake appropriately than is suggested by studies using covert manipulations. This issue is important when transferring the results of laboratory studies into the real world, and particularly where the results of laboratory studies may deter individuals or professionals from making or following recommendations. One current example lies in the recommendations to consume dark chocolate.

The consumption of dark chocolate (high-cocoa, flavanol-rich) has recently been positively associated with health benefits, including improved endothelial function and coronary circulation (Faridi et al, 2008, Flammer et al, 2007, Hermann et al, 2006, Shiina et al, 2009, Vlachopoulos et al, 2005), blood pressure (Grassi et al, 2005, Shiina et al, 2009, Vlachopoulos et al, 2005), insulin sensitivity (Grassi et al., 2005), and lipid profiles (Jia et al., 2010), to result in suggestions that individuals may benefit from the daily consumption of dark chocolate at levels of 40–60 g/day (e.g. Flammer et al, 2007, Hermann et al, 2006). Benefits are suggested to result from both specific flavanols and antioxidants, and from the possible synergy of multiple components as found naturally in both cocoa and chocolate (Flammer et al, 2007, Hermann et al, 2006), but until mechanisms are elucidated and/or specific components can be isolated, suggestions for health benefits focus on the consumption of dark chocolate and dark chocolate-based products as whole foods (Flammer et al, 2007, Hermann et al, 2006).

Chocolate, however, is an energy-dense, sweet, high-fat, highly pleasurable food (Dillinger et al, 2000, Hetherington, 2001), and concerns regarding negative impacts on body weight and obesity have been voiced (e.g. Golomb et al, 2012, Zomer et al, 2012). Sweet, high-fat foods have previously been suggested to contribute disproportionately to growing increases in obesity and body weight (e.g. see Lawton et al, 1998, Mazlan et al, 2006), and chocolate is among the most sought after of these sweet high-fat foods (Hetherington, 2001). Chocolate is also often consumed as a snack food (ie. outside of meals) (Bes-Rastrollo et al, 2010, Dillinger et al, 2000), and the contribution of high-fat snacks to increased energy intake and body weight has also been suggested (Bes-Rastrollo et al, 2010, de Graaf, 2006, Hill et al, 2003, Mazlan et al, 2006). Repeated studies suggest that the energy content of snacks particularly, is poorly compensated for in daily energy intakes, resulting in increased cumulative intakes and increased body weights over the longer term (e.g. Bes-Rastrollo et al, 2010, Mazlan et al, 2006).

Concerns of poor energy compensation often stem from studies using covert manipulations. Individuals consuming dark chocolate in the real world, however, will be very aware that they are doing so, and will be aware (or can make themselves aware) of the potential implications of chocolate consumption for their weight and health. Consuming dark chocolate in the real world thus, in full knowledge of the fact, may have much less of an impact on body weight and weight-related health than would be suggested from studies using covert manipulations. A recent epidemiological study in fact, demonstrates frequent chocolate consumption to be associated with a low, not a high body weight (Golomb et al., 2012). The demonstration of good compensation for previous consumption using a more realistic scenario may allay fears regarding the impact of recommendations to consume chocolate on body weight. This study aimed to investigate the impact of consuming dark chocolate on subsequent appetite using commercially available foods and fully complicit consumers.