This was the topic addressed by Dr. Heather Leidy from the University of Missouri and Dr. Donald Layman, Director of Research for the Egg Nutrition Center and Professor Emeritus from the University of Illinois at the annual Institute of Food Technology Wellness Conference on February 27 in Chicago.
Dr. Leidy opened the program with an evaluation of current dietary intakes and recommendations and a review of new research about benefits of higher protein diets. She reported that currently in the United States, adult protein intakes average about 0.9 to 1.1 g/kg of body weight or about 13% to 18% of energy intakes. These intakes are above the minimum requirements established by the USDA Recommend Dietary Allowance (RDA) of 0.8 g/kg leading to the general conclusion that adults eat sufficient protein. However, new research evaluating physical performance and long-term muscle function has begun to question if meeting minimum requirements to prevent deficiencies is adequate for optimum health and performance. Diseases such as obesity, diabetes, osteoporosis, and sarcopenia are increasingly prevalent and relate to muscle health. Dr. Leidy summarized new research showing benefits of higher protein diets for weight management, improving muscle function, lowering body fat, increasing energy expenditure, enhancing satiety, and helping to stabilize blood sugar and improve insulin sensitivity. Dr. Leidy emphasized the need for new and better methods for defining protein needs for optimum muscle health.
Dr. Layman reported that there is a major shift occurring in our understanding about protein needs for adults from current dietary recommendations defining protein needs as either g/kg or as % of calories to a need for specific amounts of protein at individual meals. He discussed new research about the roles of individual amino acids in metabolic signaling and the unique role of leucine as a dietary trigger for building new proteins in muscle. Leucine is an essential amino acid found in high quantities in dairy and eggs. Dr. Layman discussed his research in evaluating this unique metabolic trigger. The research shows that the leucine signal represents a meal threshold for protein requiring at least 30 g of high quality proteins to allow the body to begin to build and repair muscle proteins. Based on USDA dietary surveys, most Americans consume over 65% of their daily protein in the dinner meal with breakfast and lunch containing less than 20 g. Dr. Layman showed the importance of 30 g of protein at breakfast for long-term muscle development and body composition. Athletes also have a need for protein after exercise to accelerate recovery. The research suggests that at least 15 g of protein consumed within 2 hours after exercise will stimulate muscles to rebuild and repair proteins after intense training.
The session provided new insights about protein needs for athletes to maximize muscle performance and important information for active adults to maintain fitness and muscle function.