Cédula de conclusión

When considering the influence that the different components of appetite (hunger, satiation and satiety) have on food intake and the evidence that ingestion during sedentary screen based media use, may increase body mass in boys during mid-to-late childhood, further research should utilise rigorous methods to assess EI. In doing so, it will provide a more accurate assessment of the amount of energy consumed during the use of screen based media and could be used to give insight into relative energy balance.

Assessment of children’s EI is beset with challenges related to participant age, cognitive ability and weight status (Livingstone & Robson, 2000). Prior to the measurement of children’s EI, the

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outcome of the assessment, the dietary component that requires measurement, the population group being investigated and the time period of monitoring, must all be considered (Bates, Nelson, &

Ulijasek, 2005). Dietary assessment can be carried out using prospective and retrospective methods, all of which have strengths and limitations (Collins, Watson, & Burrows, 2010).

Retrospective approaches such as, diet history, 24 h recall and food frequency questionnaire are some of the most commonly utilised methods. These methods however are subject to bias caused by participant memory, which can then lead to underestimation of important elements such as portion sizes (Frobisher & Maxwell, 2003). Under-reporting of unhealthy foods and over-reporting of healthy foods have also been found to occur in children and when compared to total EI, measured by doubly-labelled water (DLW), both behaviours are known to increase with child age (Champagne, Bray, Kurtz, Monteiro, & et al., 2002).

Prospective methods of EI assessment include weighed food records and food checklists. Weighed food diaries are one of the most widely used measures which require the participant to weigh and record all food and drink items prior to and following ingestion. This particular method and indeed all of those previously mentioned, are only appropriate when an assessment of the previous EI of the individual is required over a designated period of time (Collins et al., 2010).

For short-term intervention studies, that require the presence of the researchers and the measurement of participant dietary intake in the interim, direct observation is the most appropriate method. In a controlled setting and when providing food and drinks ad-libitum, direct observation is a prospective method that gives the most accurate measure of EI. Prior to offering the food and drinks, they are weighed or measured so that each item consumed can be recorded. Anything left over is also weighed or measured, enabling the total amounts of food and drinks consumed to be calculated (Bates et al., 2005). The disadvantages of direct observation are that it is labour intensive and good literacy and numeracy skills are essential. The advantages of direct observation however outweigh the aforementioned disadvantages for short-term or acute intervention studies.

Participants are not aware their food intake is being measured. Therefore, problems such as deliberate reporting, avoidance of certain foods to reduce total EI and unintentional under-reporting are usually averted (Macdiarmid & Blundell, 1998). Furthermore direct observation is a

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method that has been used by the more meticulous paediatric appetite studies that have monitored and assessed the food and drink intakes of participants during short-term interventions (Dodd, Welsman, & Armstrong, 2008; Rumbold, Dodd-Reynolds, & Stevenson, 2013; Rumbold, St Clair Gibson, Allsop, Stevenson, & Dodd-Reynolds, 2011; Rumbold et al., 2013).

It is considered rigorous to standardize EI prior to appetite intervention studies. Changes in volumes of EI and macronutrient composition affect the time of digestion and absorption (Claessens, van Baak, Monsheimer, & Saris, 2009), which subsequently influences appetite. It is desirable therefore for participants to be in the same post-ingestive state during EI interventions wherein appetite is also measured (Flint, 2000; Flint, Raben, Ersbøll, Holst, & Astrup, 2001). The method of standardization must however be suitable for the study population to ensure compliance and accuracy and prevent drop-out. Weighed food diaries are one of the most widely used methods of EI assessment and their accuracy has been corroborated with DLW in children aged 7 y and 9 y (Livingstone et al., 1992). At 9 y, the children with the help of parents were also noted to show enthusiasm and interest in the weighing and reporting their food intake (Livingstone et al., 1992;

Livingstone & Robson, 2000). However, essential dietary data can still be inaccurately reported such as portion sizes and whether any food or drink item was left over, so the use of two separate methods combined, is recommended in paediatric studies (Livingstone & Robson, 2000).

To counteract potential missing detail from children’s weighed food diaries, Dodd and colleagues (2008) utilised the two pass 24 h recall method in combination (Ashley & Bovee, 2003). This latter approach is recommended for use in studies in which the design includes a free-living element (Livingstone & Robson, 2000) and has proved successful in acute appetite studies with 8-12 y females. The 24 h recall method is advantageous due to it being inexpensive, time efficient, not dependent upon literacy level and it accumulates precise detail, thus has low participant burden (Hill, Rogers, & Blundell, 1995; McPherson, Hoelscher, Alexander, Scanlon, & Serdula, 2000) At the time Dodd and colleagues (2008) utilised the combined method of weighed food diary and 24 h recall it had not been assessed in terms of accuracy in a paediatric population. Such assessment came later, when the precision of the combined method was tested in the laboratory by Rumbold and colleagues (2011). The 24 h EI of 13-15 y old girls was monitored and measured by trained

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researchers and assessed against each participant’s ability to accurately complete a weighed-food diary and then recall their EI, 24 h later. Even though the population in the cited study were of an age whereby underreporting can increase (Bratteby, Sandhagen, Fan, Enghardt, & Samuelson, 1998; Livingstone et al., 1992), there was good agreement for the method between the participants and researchers on a group level (Rumbold, et al., 2011). On considering the evidence from the above two cited studies, the combined method of self-reported weighed food diary and 24 h recall appears to be the most robust and efficient technique to ensure standardisation of food intake, prior to an appetite-related intervention in paediatric populations which includes a naturalistic element.