Colic is often defined by the rule of threes - crying more than 3 hours a day, more than 3 days a week, for more than 3 weeks. Parents usually report increased gas and gas-related symptoms in these babies. Difficulty digesting specific carbohydrates can lead to increased gas. A study published in the May 2002 issue of Pediatrics divided babies (averaging 5 months old) into two groups, those who had, and those who had not, been diagnosed with colic at some point during the first 6 months. Each baby received a 4-ounce serving of apple juice and a 4-ounce serving of white grape juice, and was monitored in a metabolic chamber for 3 hours after each serving. The observers did not know which babies were which. Those in the colic group proved to have significantly poorer absorption of the sorbitol and of the elevated fructose in the apple juice (as shown by measuring increased hydrogen gas in their breath). They also were more agitated, spent more calories, cried more, and slept less after the apple juice. Their non-colic peers had no detectable problem digesting the apple juice. Both groups tolerated the non-sorbitol, lower-fructose white grape juice without a problem. Some kids have a harder time digesting certain carbohydrates than others. Avoiding those carbohydrates can lead to less gas and more peace.