12 people in the whole world are known to lack the appetite regulation hormone leptin. 2 leptin deficient teens were found to rate even broccoli as very tasty.
Without leptin, the two teens wanted to eat non-stop. The boy weighed 103 kilograms by age 14 and the girl weighed 128 kilograms at 19 years old. As part of the study, the researchers asked them to rate how much they liked various foods, ranging from chocolate cake to broccoli, and discovered that they rated bland foods unusually highly.
These teens had unusual activation patterns in an area of the brain called the nucleus accumbens. Leptin therapy caused their appetites to become more normal. They also lost their appetite for broccoli.
Farooqi then began treating the two leptin-deficient teens with the hormone and tested their brain response to various foods one week later. After receiving leptin therapy, the nucleus accumbens of the subjects only became activated by foods when they had not eaten for several hours.
If you can't keep your weight down then blame it on your genes.
Studies suggest that genetics accounts for 40 to 70 percent of adult body weight, but researchers don't know all the culprits. Four years ago, Farooqi's group discovered that a separate mutation in the gene for melanocortin-4 receptor shows up in 1 percent of obese people and 5 to 6 percent of severely obese children.
Offspring genetic engineering will eventually make obesity very rare. Even before then better appetite control drugs will greatly reduce problems with excess weight. This study suggests that a leptin mimic drug might reduce appetite and make weight control much easier.
|Share |||Randall Parker, 2007 August 14 12:28 AM Brain Appetite|