The differential diagnosis of chronic diarrhea varies markedly with age. In infants, it is usually a problem with formula intolerance. Because there is up to a 50% crossover intolerance between milk and soy, the infant should be given an extensively hydrolyzed formula. If such intervention is delayed, he or she may develop intractable diarrhea of infancy. Most affected toddlers have either irritable colon of infancy or protracted viral enteritis with low-grade mucosal injury and are consuming hypertonic feedings. In either case, institution of a high-fat, low-carbohydrate diet that includes whole milk often results in significant improvement. Dietary lactose rarely is a problem. A likely cause of diarrhea among children and adolescents is inflammatory bowel disease. With the exception of toddlers, chronic diarrhea suggests the presence of significant organic disease.

JPEN J Parenter Enteral Nutr 1985 May-Jun;9(3):361-3
Beneficial effects of fasting and low carbohydrate diet in D-lactic acidosis associated with short-bowel syndrome.
Ramakrishnan T, Stokes P.
A case of D-lactic acidosis in an 18-yr-old man with a short bowel is reported. The diagnosis, suspected on clinical grounds, was confirmed by serum and urine levels of D- lactate. Our studies revealed that an ad libitum diet was associated with elevated D-lactate levels and "nothing per oral" and 10% carbohydrate diet regimens caused a drop in D- lactate levels. We recommend npo and low carbohydrate diet as preferred alternatives to antibiotics in some patients with D-lactic acidosis. The literature is reviewed.