Ahmed Ahmed Swaid, a qat merchant, sits on a rooftop in the old Yemeni city of Sanaa with his typical day's worth of food. (From the book What I Eat: Around the World in 80 Diets.) The caloric value of his typical day's worth of food in the month of April was 3300 kcals. He is 50 years of age; 5 feet, 7 inches tall; and 148 pounds. Ahmed, who wears a jambiya dagger as many Yemeni men do, has been a qat dealer in the old city souk for eight years. Although qat chewing isn't as severe a health hazard as smoking tobacco, it has drastic social, economic, and environmental consequences. When chewed, the leaves release a mild stimulant related to amphetamines. Qat is chewed several times a week by a large percentage of the population: 90 percent of Yemen's men and 25 percent of its women. Because growing qat is 10 to 20 times more profitable than other crops, scarce groundwater is being depleted to irrigate it, to the detriment of food crops and agricultural exports. MODEL RELEASED.