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Introduction 1

Here is the introduction of an article from Clinical Nutrition (2005: 24, 885-895) entitled: Effects of physical activity on food intake by Melzer, Kayser, Saris and Pichard.

Notice that some stages are shorter than the others. This will vary across articles as some authors spend longer reviewing the literature while others take longer to build a case for their own research. The highlighted text shows you how argument is built up in this introduction, justifying the aim of this article.

Click on the gray text in the right hand column to see how this works.

Stage and purpose of the stage   
1. ESTABLISHING THE FIELD

- asserting importance of the topic

- stating current knowledge (generally)

Physical activity (PA) is closely interrelated with energy intake. The working body requires energy and nutrients in order to fuel activity and function. PA, on the other hand, manipulates energy expenditure and regulates the use of fuels.

2. SUMMARISING PREVIOUS RESEARCH

- from the perspective of this research

When prolonged strenuous PA is performed on a regular basis, it causes an increase in overall energy turnover1 and leads either to loss of body weight, or to a need for an increase in food intake.2

3. PREPARING FOR PRESENT RESEARCH

Justifying this research by

- indicating a gap

- raising a question

Nevertheless, many questions remain open in that regard. For example: is increased energy expenditure due to short-term PA automatically compensated for by changes in energy intake? Does shortterm exercise have the same effect on energy intake as long-term exercise? Does the eventual increase in food intake due to increased PA follow the same pattern in obese as in lean individuals?

Here the authors signal that what they have discussed so far is not the whole story − there is a gap in current understandings about the research and that many questions have not been addressed by the research.

 

Thus, to which extent the energy intake is regulated through PA still remains unclear and further research is required that may provide useful information for public health guidelines. For example, vigorous PA on a daily basis not only increases the overall intake of energy,3 but also of other constituents of food, such as micronutrients. Therefore, in conjunction with low-energy food abundant in minerals and vitamins, PA may not only enhance human health in general,4 but also prevent micronutrient deficiencies.5

Building on their argument in the previous paragraph, the authors further justify the need for their research and conclude that more research needs to be done to clarify the relationship between PA and energy intake.

4. INTRODUCING PRESENT RESEARCH

- stating purpose and aims

Therefore, reaching a clear understanding of the relationship between PA and food intake may prove valuable in choosing the most beneficial approach for individual and societal health management. The aim of this paper is thus to summarize the state-of art in our understanding of the effects of PA on energy and nutrient intake.

Having set up the justification for the authors' research in the previous paragraph the authors can now propose that their research − which will summarise the literature on the topic − will help to clarify the understanding of the relationship between PA and energy intake.

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