This chapter comprehensively explores the complex topic of protein requirements in the elderly, focusing on various factors that influence protein utilization and muscle health. It delves into the quality of protein sources, highlighting the differences between animal and plant-based proteins and their impact on health outcomes in aging individuals. Additionally, it emphasizes the significance of distributing protein intake evenly throughout the day and the synergistic role of physical activity in promoting muscle health in older adults. The chapter also introduces new methods for assessing protein quality, such as the digestible indispensable amino acid score (DIAAS), which provides a more accurate reflection of essential amino acid bioavailability. Ultimately, the chapter underscores the importance of a holistic approach, considering not only protein quantity but also quality, meal distribution, and physical activity to support healthy aging and maintain muscle mass in the elderly. <!----> <!----> <!----> <!---->

Mediterranean diet (MD) is regarded as one of the healthier dietary patterns which is recommended for athletes. This study aims to investigate the adherence to the Mediterranean diet (AMD) and associated beliefs in a large, diverse sample of competitive adolescent athletes from various sports, including both lean and non-lean sports. Additionally, the study examines factors important regarding intention to AMD within the Theory of Planned Behavior (TPB). In the study took part 711 adolescents (357 male, aged = 14.93 ± 1.38, and 354 female, aged = 14.85 ± 1.35) athletes. The level of AMD was not a significant different between lean (mean = 4.98, SD = ±3.90) and non-lean (mean = 4.77, SD = ±3.68) sport. According to the sport type the 35% of lean sport athletes demonstrated low AMD, 34.1% moderate adherence and 30.9% a high degree. The non lean athletes demonstrated low AMD in 36.3%, moderate adherence 33% and high degree in 30.7%. The results of the mediation analysis indicated a significant mediation effect of intention in the relationship between TPB variables and MD. Based on the results of the study the type of sport does not play a role in the AMD, which, as in the general population, is low. Also validate the TPB and underscore the significance of targeting individuals’ intentions to promote positive dietary behaviors.

Background/Objectives: Valid and culturally adapted instruments are essential for accurately assessing sports nutrition knowledge among coaches, given their influential role in shaping athletes’ dietary behaviors and performance outcomes. This study aimed to translate, culturally adapt, and evaluate the psychometric properties of the Nutrition for Sport Knowledge Questionnaire (NSKQ) for Greek certified coaches, while also examining knowledge levels and associated demographic factors. Methods: A cross-sectional study was conducted among 514 certified coaches representing various sports disciplines. The translation followed a standardized forward–backward procedure with expert panel review to ensure cultural relevance. The psychometric properties of the NSKQ-Gr were evaluated using complementary Classical Test Theory (CTT) and Rasch approaches. Item difficulty, item discrimination, Kuder–Richardson Formula 20 (KR-20), McDonald’s omega, and confirmatory factor analyses (CFAs) using the WLSMV estimator for dichotomous items were performed. Test–retest reliability was examined via Pearson’s correlation coefficient and intraclass correlation coefficient (ICC). Statistical analyses explored associations between nutrition knowledge and demographic and professional characteristics. Results: Item discrimination varied across domains; the strongest performance was observed for the Alcohol domain and the weakest for Weight Management and Sports Nutrition. KR-20 and McDonald’s omega indicated moderate internal consistency for most domains, apart from Weight Management and Sports Nutrition, the reliability of which was lower. The temporal stability was excellent (ICC = 0.998). CFA findings were heterogeneous across domains, whereas Rasch analyses showed generally acceptable item-level fit. Most coaches demonstrated average (56.8%) or poor (32.3%) sports nutrition knowledge. Good or excellent knowledge was demonstrated by only 10.9% of the participants. Knowledge scores differed according to age, certification pathway, previous athletic experience, and several nutrition-related coaching practices. Conclusions: The NSKQ-Gr provides a useful multidomain instrument for assessing sports nutrition knowledge among Greek coaches. The present study extends previous validation work by providing complementary evidence from CTT, CFA, and Rasch modeling, thereby offering a more comprehensive psychometric evaluation of the NSKQ-Gr. The findings indicate that the NSKQ-Gr is a multidomain knowledge assessment instrument suitable for Greek coaches. Future validation studies are encouraged to further refine its psychometric properties.