The professional who assesses diet and nutrition for health improvement is a registered dietitian (RD). Dietitians use their expertise in nutrition science to provide personalized dietary recommendations tailored to individual health needs, medical conditions, and lifestyle factors. They offer support for various issues, such as weight management, chronic diseases, and sports nutrition. By collaborating with clients, dietitians develop effective strategies for achieving optimal health through evidence-based nutritional guidance, enabling individuals to make informed decisions about their food choices and dietary habits.