The Influence of Short‐Term, Severe Low Energy Availability With Varying Protein Content on Substrate Metabolism, High‐Intensity Exercise Performance and Subjective Responses in Young Adults

, with all macronutrients reduced proportionally); and another LEA condition but with protein matched to AEA (LEA-P). They returned to the laboratory on the 5th day to repeat all experimental tests. Participants also completed brief, semi-structured interviews to explore their subjective responses to each condition. Results indicated that both the LEA and LEA-P diets induced a shift towards increased fat oxidation at rest, but not during exercise, compared to AEA. In contrast, Wingate performance declined only in the LEA-P trial compared to AEA, potentially due to its reduced carbohydrate content. Participants generally reported negative experiences during both calorie-restricted trials, including hunger, fatigue, weakness and frustration, with symptoms appearing more pronounced in males and during the LEA trial.