It seems improbable that a baby born underweight would be prone to obesity, but it is well documented that these children tend to put on weight in youth if they're allowed free access to calories. Now, researchers believe they understand why this happens.
A new animal model study at UCLA has found that in low–birth-weight babies whose growth was restricted in the womb, the level of appetite-producing neuropeptides in the brain's hypothalamus — the central control of the appetite — is higher, resulting in a natural tendency among these children to consume more calories.