Weight class-restricted and aesthetic athletes have unique requirements related not only to the metabolic and adaptive demands of their sport and training, but also related to their body composition and the stress and psychological demands of dieting. While traditionally recommended protein intakes are likely appropriate for athletes during energy balance or surplus, there are potential benefits to exceeding this amount during periods of energy deficit. Lean individuals experienced with resistance training may undergo reduced losses of fat free mass (FFM) when they consume higher protein intakes based on the findings in Chapter 2. Furthermore, Chapter 3 highlights the potential benefits of reduced mood disturbance, fatigue and athlete-specific stress when consuming protein intakes above traditionally recommended levels during caloric restriction.

However, energy balance itself is likely a more important factor than protein intake alone. Slower weight loss rates and more moderate caloric restriction protects against performance and FFM losses. A gradual approach to weight loss rather than an aggressive one can be a more effective strategy for FFM and performance retention given ample planning and time. Care should be taken to ensure that adequate calories are consumed during periods of energy restriction. This ensures that when protein is increased, neither fat nor carbohydrate is driven too low.

Future research is required to determine how the effects of higher protein intakes impact body composition, performance and psychometric variables in lean resistance-trained athletes for longer time periods than have yet been studied. Questions also remain as to the effects of other macronutrient combinations and levels of caloric restriction. Finally, the majority of available studies in this area examine men; similar research in female athletes is severely lacking and needed.