Protein nutrition fasting

Amino Add Supplements Complementary Proteins Clinical Issues in Protein Nutrition Modified Fasting Chronic Renal Failure Hyperuricemia Wasting in Cancer and AIDS References Bibliography... 

The second half of this chapter concerns material of a less biochemical and a more nutritional nature. Three t5q es of protein nutrition are illustrated by studies with humans (1) the total fast, (2) the carbohydrate-only fast, and (3) a diet intended to maintain nitrogen balance. 

Total fast As far as protein nutrition is concerned, the total fast is the most severe condition. During a total fast, the loss of urinary nitrogen is equivalent to about 80 g of the body s proteins. 

Fats are much more energy-rich than carbohydrates, proteins, or ketones. Complete combus- i tion of fet results in 9 kcal/g compared with 4 kcal/g derived from carbohydrate, protein, and j ketones. The storage capacity and pathways for utilization of fuels varies with different organs and with the nutritional status of the organism as a whole. The organ-specific patterns of fuel utilization in the well-fed and fasting states are summarized in Table I-ll-l. 

Nutritional therapy for HMG-CoA lyase deficiency has two major goals. First, the prescribed diet aims to provide enough total protein and calories to achieve normal growth and maintain metabolic balance in the context of a leucine-restricted diet. Equally important, the nutritional therapy focuses on preventing excess catabolism, acidosis, and hypoglycemia, especially during times of acute illness. For these patients, it is particularly important to avoid fasting at any time. 

When food intake decreases, the utilization of fat and protein reserves in the body enables various essential metabolic processes to continue during the nutritional inadequacy. In the early stage of fasting or starvation, glucose requirements of the brain and nervous system are fulfilled by mobilization of glycogen in the liver. This short-term adaptation lasts only a day until glycogen stores are exhausted. Gluconeogenesis... 

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