The time of day is a factor that influences the optimization of sports performance. Schedules are usually adjusted according to convenience or availability and resources. However, few studies have specifically investigated the effect of early morning versus afternoon-evening training on fatigue indices in performance. This is important from a sports perspective because circadian rhythms, player readiness, and alterations in sleep or meal patterns can affect performance [13]. The growth development and talent detection of an athlete can be determined through different measurement methods, with anthropometry being the most commonly used [14]. Anthropometry refers to the various measurements of the size and proportions of the human body [14; 15; 16]. One institution involved in disseminating anthropometry is the International Society for the Advancement of Kinanthropometry (ISAK), which was founded as an organization whose scientific and professional work is related to kinanthropometry [17]. Furthermore, anthropometric techniques stand out among various composition assessment methods due to their low cost, good reproducibility, and ease of application [15]. In fact, skinfold measurements and their sum seem to be the least affected by control factors (hydration intake and daily activity) compared to other measurement methods [18]. A balanced diet is recognized as an important factor in aiding the proper functioning of our bodies and thus maximizing training effectiveness. A crucial factor for athletes is the meeting of their energy needs, which we refer to as energy balance, i.e., when energy intake equals energy expenditure. This relationship influences sports performance and makes it vital that during physical activity, the organism's needs are met, including energy requirements, adequate intake of macro and micronutrients, and optimal hydration in accordance with the training plan, competition cycles, and other factors, such as exposure to cold, heat, high altitude, injuries, medications [19] or, as in the case of our study population, the time of day at which training occurs [9]. In addition, the group we are discussing consists mostly of young individuals still in development, who require adequate energy intake to ensure proper growth and development [20]. Given the scarcity of scientific research examining potential differences in the time of day (TOD) of training on body composition and diet in young elite athletes, who often have different training schedules due to the demands of their sport, the main objective of this study was to descriptively analyze potential differences in body composition and energy and nutrient consumption between the morning training (MT) group and the evening training (ET) group. The aim of this study was to analyze differences in anthropometric characteristics, estimation of energy expenditure and consumption, as well as intake of macronutrients and micronutrients in elite youth soccer players from the Spanish league with different training schedules (morning and evening). Consequently, the initial hypotheses were as follows: Hypothesis 1 (H1): The time of day of training will reflect differences between the morning training group and the evening training group in terms of body composition. Hypothesis 2 (H2): There will be differences in nutrient intake due to different mealtimes between both groups.