Fruits, vegetables and animals can be 100 percent organic. What about people?

In a fascinating experiment  on himself  Dr. Alan Greene, a pediatrician and author in Danville, Calif., decided to find out. For the last three years, Dr. Greene has eaten nothing but organic foods, whether he’s cooking at home, dining out or snacking on the road.

He chose three years as a goal because that was the amount of time it took to have a breeding animal certified organic by the Department of Agriculture. While food growers comply with organic regulations every day, Dr. Greene wondered whether a person could meet the same standards.

It hasn’t been easy.

“This isn’t a way of eating I could recommend to anybody else because it’s so far off the beaten food grid,” said Dr. Greene, 49, the founder of a popular Web site about children’s health, drgreene.com. “It was much more challenging than I thought it would be, and I thought it would be tough. There were definitely days where there was nothing I could find that was organic.”

Other writers have ventured off the traditional food grid, notably Barbara Kingsolver in “Animal, Vegetable, Miracle” and Michael Pollan in “The Omnivore’s Dilemma.” But what makes Dr. Greene’s experiment remarkable is the length of time he devoted to it, and his effort to incorporate organic eating into the routines of everyday living. His findings offer new insight into the challenges facing the organic food industry and those of us who want to patronize it.