Study links hormone to diet, exercise

The finding is important, one official said.
SCRIPPS HOWARD NEWS SERVICE
"Eat less, exercise more" is the mantra of most weight-loss protocols. Now scientists have discovered that a hormone appears to encourage us to do just that.
A small study by British researchers found that overweight but otherwise healthy volunteers both reduced food intake and increased physical activity upon receiving injections of the hormone oxyntomodulin three times a day, once before each meal.
The hormone, found in the small intestine, is normally released as food is consumed to signal the brain to stop eating. Scientists, including the team at Imperial College London that did the new study, had already shown that boosting levels of the hormone could reduce body weight and food intake in overweight people.
Patients with higher levels of oxyntomodulin have also been found to have reduced levels of the appetite hormone leptin and other hormones that encourage the body to store energy as fat.
"The discovery that this hormone has a double effect, increasing energy expenditure as well as reducing food intake, could be of huge importance," said Steven Bloom, a senior researcher at the college and Hammersmith Hospital in London and lead author of the report, published online Wednesday by the International Journal of Obesity.
How it worked
Bloom's team worked with 15 male and female volunteers, ages 23 to 49. Each subject completed three separate four-day study sessions, when they self-administered either saline or oxyntomodulin. Neither the volunteers nor the researchers knew who got the active doses.
After the first injection of each session, which began in the hospital, the volunteers got a meal and their caloric intake was monitored. They then spent two days at home, taking an injection three times a day before meals. On the fourth day, they returned to the hospital where their energy expenditure was measured.
The researchers found that the volunteers taking the hormone ate, on average, 17 percent less than they did before the injections, while activity-related energy expenditures increased by an average of 26 percent. The researchers also found that volunteers taking the hormone had a body-weight reduction of 0.5 percent, or equal to the loss of about a pound a week. Those getting the saline injections had no significant response.