Dietary intake of professional Australian football athletes surrounding body composition assessment

Australian football (AF) is an intermittent high intensity team sport with intense periods of play, interspersed with periods of recovery [1]. At the professional level, Australian football (AFL) athletes train over a season that is divided into pre-season (~ 4 months) and competition (~ 6 months) phases. Training demands are substantial with athletes covering up to 30 km of total distance during a typical pre-season week, with a modified training volume performed in-season with the addition of match-play [2]. Moreover, athletes complete other training modalities (i.e. weights, cross training) to complement these running volumes in preparation for match demands. For a professional AFL athlete to meet training and performance demands and achieve body composition goals, energy and macronutrient intakes must reflect training and competition loads [3]. Therefore, dietitians have increasingly become recognized as an integral part of high performance teams. Their role is to promote optimal nutrition and to support, direct and teach sustainable nutrition practices to athletes in accordance with their training loads and body composition goals. Advice provided by accredited dietitians is guided by evidence-based recommendations that focus on periodization of energy, macronutrient and fluid intake, according to individual characteristics and body composition goals [4, 5].

Due to the high intensity nature of AF training and match play; adequate energy intake is required to maintain lean muscle mass, refuel energy stores and promote optimal performance [6]. However, research has reported that athletes across a range of team sports consistently fail to meet energy and carbohydrate recommendations [3, 6, 7]. The difficulties athletes experience when trying to consume a well-balanced diet and meet energy recommendations have also been reported [8, 9]. Many individual and environmental factors including knowledge and skills, peers and team culture, time constraints, finances and access to healthy food have been found to influence the dietary intake of athletes [6, 8, 1012].

Nutrition knowledge (NK) is also thought to influence the dietary intake of individuals [11]. General knowledge behaviour models suggest that if an individual is aware of the benefits of nutrition they are more likely to make informed decisions regarding their health [13]. The link between NK and dietary behaviours has been examined in previous research, with weak to moderate positive associations reported in a variety of athletes [6, 7, 11]. While this research has underlined the importance of athlete NK and subsequent behaviour, most studies have only observed small samples of team sport athletes and used NK assessments that do not correspond with current IOC intake recommendations [14].

Coaches and high performance staff often assign athletes body composition goals such as reducing body fat and increasing lean muscle mass to develop a physique that can tolerate training loads and match demands [3]. Although body composition goals are present in professional sport, no research has established the impact of these goals on adequate intake. These goals are likely to influence the dietary intake of athletes, particularly during times of body composition assessment. However, in efforts to achieve body composition goals, restriction of dietary intake may occur and in times of high training loads may impair recovery, increase the likelihood of injury or illness and decrease overall performance (i.e. symptoms of overtraining) [8, 15, 16]. Body composition measurements may be collected during different training phases, so it is important to explore the extent to which body composition goals influence dietary intake, to inform strategies to support athletes to maintain adequate dietary intake required for performance.

Our primary aim was to examine the energy and macronutrient intakes of AFL athletes during a pre-season training week where body composition assessments were undertaken. Secondary aims included assessing intake of other nutrients and athletes’ NK as well as relationships between intake and factors including: age, playing experience and education status. We hypothesised that athletes were likely to have inadequate dietary intakes surrounding body composition assessment.