WASHINGTON — The number of troops diagnosed as overweight or obese has more than doubled since the start of the Iraq war, yet another example of stress and strains of continuing combat deployments, according to a recent Pentagon study. The review, contained in the January edition of the Defense Department's Medical Surveillance Monthly Report, raises concerns about the overall readiness as demands on the military continue to increase, says Dr. Michael Kilpatrick, director of strategic communication for Pentagon health affairs. "Stress and return from deployment were the most frequently cited reasons" for gaining weight, the study said. The largest increase in diagnoses of overweight and obese troops came in the last five years, the report said. From 1998 to 2002, the number of servicemembers diagnosed as overweight remained steady at about one or two out of 100. But those numbers increased after 2003, according to the study, and today nearly one in 20 are diagnosed as clinically overweight. There may be even more overweight troops than the report shows, Kilpatrick said, because the study includes only servicemembers diagnosed as overweight during a visit with a doctor. The actual percentage of troops who are found to be overweight during fitness trials could be higher, he said. The weight-gain trend is among many strains shown within the military after six years of war and back-to-back deployments. They include steadily rising suicides and divorce rates among soldiers and Marines and increased prescription drug use in the Army. Problems with obesity among the general public — fostered by fast-food restaurants and increasingly popular sedentary pastimes such as video games — have spilled over into the military, the study suggests. One in five Americans between ages 18 to 34 is obese, the study says. The Army reports problems of obesity among recruits. "Overweight/obesity is a significant military medical concern because it is associated with decreased military operational effectiveness," the study says.