At three weeks of age, the rat pups fed the high-carbohydrate (HC) formula were then weaned onto rat chow either with free access to food or with a moderate calorie restriction, so that their level of consumption would be the same as pups reared naturally.
"When food intake for the HC rats was controlled to a normal level, the pups grew at a normal rate, similar to that of pups fed by their mothers," Patel says. "But we wanted to know, did that period of moderate calorie restriction cause the animals to be truly reprogrammed? We knew that the proof would come once we allowed them to eat ad libitum, without any restrictions.
"We found that when the HC rat undergoes metabolic reprogramming for development of obesity in early postnatal life, and then is subjected to moderate caloric restriction, similar to when an individual goes on a diet, the programming is only suppressed, not erased," he says.
This is due to developmental plasticity, which extends from fetal development into the immediate postnatal period. According to Patel, previous research by others has revealed that during the immediate postnatal period, pancreatic islets and neurons continue to mature.
"That's why an altered nutritional experience during this critical period can independently modify the way certain organs in the body develop, resulting in programming effects that manifest later in life," Patel says. "During this critical period, the hypothalamus, which regulates appetite, becomes programmed to drive the individual to eat more food. We found that a period of moderate caloric restriction later in life cannot reverse this programming effect."
Therefore, addressing the obesity epidemic in the U.S. requires true lifestyle change, including permanent caloric restriction.
"As long as you restrict intake, you can maintain normal body weight," he says.
To avoid metabolic reprogramming that predisposes a baby to obesi
|Contact: Ellen Goldbaum|
University at Buffalo