Understanding meal patterns: definitions, methodology and impact on nutrient intake

Breakfast of omelette, potatoes and toast

This month’s featured paper is from Nutrition Research Reviews journal, and is entitled ’Understanding meal patterns: definitions, methodology and impact on nutrient intake and diet quality'.  The team, Rebecca M. Leech, Anthony Worsley, Anna Timperio and Sarah A. McNaughton from the Centre for Physical Activity and Nutrition Research (C-PAN), School of Exercise and Nutrition Sciences, Deakin University reports on the review of literture on adults' meal patterns, including how meal patterns have previously been defined and their associations with nutrient intakes and diet quality.

A recent shift in nutrition research has been towards examining dietary patterns which acknowledges that individual nutrients and foods are highly interrelated.  However a poorly understood, yet fundamental step between the intake of individual nutrients/foods and dietary patterns are meals. Examining food intakes at the level of a meal provides evidence on the way people actually consume foods. This has the potential to inform the development of messages and strategies promoting simple and feasible changes to food habits in the population.

A major barrier to interpreting studies in this field of research has been the lack of a clear definition of a meal and/or snack. The need for research to develop a standardised definition for meals and snacks was also recommended in a recent report released by the American Dietary Guidelines Committee.  The present paper summarises and critiques meal pattern research, including previous approaches to characterising, defining and measuring meals.  The implications of these approaches were also explored in relation to associations between meal patterns, energy and nutrient intakes and overall diet quality among adults. 

What we found
We found that a variety of approaches have been used to define meals with little consideration to how these definitions influence how meal patterns are characterised.  Most commonly, meals have been defined according to participant self-report and the time-of-day in which food was eaten.  However, much variation exists within these approaches, with different additional criteria being used to delineate individual meals, snacks and/or eating occasions (e.g. energy content, time intervals and treatment of beverages). Despite the diversity in meal definitions, we found that skipping breakfast was consistently associated with a poorer diet quality.  However, no consistent associations were found for other meal patterns such as snack, meal and overall eating frequency. Inconsistency in associations may arise from the subjective nature of participants’ recall of meals versus snacks. The use of different time intervals and an energy content criterion for defining an individual eating occasion may also be problematic. Notably, there was a paucity of research examining the impact of these different criteria or definitions.
Where to now?
Future research that examines the influence of different meal definitions on the characterisation of meal patterns is required to develop consensus on a standardised definition for meals, snacks and eating occasions. Refinement of existing definitions may also be assisted by a better understanding of the factors that influence participants’ decisions to classify eating occasions as meals or snacks. Addressing these methodological issues will advance the field of meal pattern research so that we can better understand meal pattern behaviours and their role in health.

View the full paper here.

Photo with thanks to Tom Purves, Flickr, reproduced under a CC license.