protein intake would be approximately 25% of energy requirements i.e. approximately 2 to 2.5 g/kg. however, many questions still remain to be resolved. in addition, some have suggested that athletes using restricted-calorie diets for weight loss should further increase their protein consumption, possibly to 1.8–2.0 g/kg, in order to avoid loss of lean muscle mass. aerobic exercise protein needs endurance athletes differ from strength-building athletes in that endurance athletes do not build as much muscle mass from training as strength-building athletes do. research suggests that individuals performing endurance activity require more protein intake than sedentary individuals so that muscles broken down during endurance workouts can be repaired. although the protein requirement for athletes still remains controversial (for instance see lamont, nutrition research reviews, pages 142 - 149, 2012), research does show that endurance athletes can benefit from increasing protein intake because the type of exercise endurance athletes participate in still alters the protein metabolism pathway. the overall protein requirement increases because of amino acid oxidation in endurance-trained athletes. endurance athletes who exercise over a long period (2–5 hours per training session) use protein as a source of 5–10% of their total energy expended. therefore, a slight increase in protein intake may be beneficial to endurance athletes by replacing the protein lost in energy expenditure and protein lost in repairing muscles. one review concluded that endurance athletes may increase daily protein intake to a maximum of 1.2–1.4 g per kg body weight. anaerobic exercise protein needs research also indicates that individuals performing strength training activity require more protein than sedentary individuals. strength-training athletes may increase their daily protein intake to a maximum of 1.4–1.8 g per kg body weight to enhance muscle protein synthesis, or to make up for the loss of amino acid oxidation during exercise. many athletes maintain a high-protein diet as part of their training. in fact, some athletes who specialize in anaerobic sports (e.g., weightlifting) believe a very high level of protein intake is necessary, and so consume high protein meals and also protein supplements. protein allergies main article: food allergy a food allergy is an abnormal immune response to proteins in food. the signs and symptoms may range from mild to severe. they may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. these symptoms typically occurs within minutes to one hour after exposure. when the symptoms are severe, it is known as anaphylaxis. the following eight foods are responsible for about 90% of allergic reactions: cow's milk, eggs, wheat, shellfish, fish, peanuts, tree nuts and soy. chronic kidney disease while there is no conclusive evidence that a high protein diet can cause chronic kidney disease, there is a consensus that people with this disease should decrease consumption of protein. according to one 2009 review updated in 2018, people with chronic kidney disease who reduce protein consumption have less likelihood of progressing to end stage kidney disease. moreover, people with this disease while using a low protein diet (0.6 g/kg/d - 0.8 g/kg/d) may develop metabolic compensations that preserve kidney function, although in some people, malnutrition may occur. phenylketonuria individuals with phenylketonuria (pku) must keep their intake of phenylalanine – an essential amino acid – extremely low to prevent a mental disability and other metabolic complications. phenylalanine is a component of the artificial sweetener aspartame, so people with pku need to avoid low calorie beverages and foods with this ingredient. excess consumption