Results of animal study suggest that human babies may be less
prone to obesity if given solid foods later
BUFFALO, N.Y. – Consumption of foods high in
carbohydrates immediately after birth programs individuals for
lifelong increased weight gain and obesity, a University at Buffalo
animal study has found, even if caloric intake is restricted in
adulthood for a period of time.
The research on laboratory animals was published this month in
the American Journal of Physiology: Endocrinology and Metabolism;
it was published online in December.
“This is the first time that we have shown in our rat
model of obesity that there is a resistance to the reversal of this
programming effect in adult life,” explains Mulchand S.
Patel, PhD, SUNY Distinguished Professor of Biochemistry and
associate dean for research and biomedical education in the UB
School of Medicine and Biomedical Sciences.
The research has applications to the obesity epidemic in the
U.S., particularly as it relates to infant nutrition, Patel
“Many American baby foods and juices are high in
carbohydrates, mainly simple sugars,” he says. “Our
hypothesis has been that the introduction of baby foods too early
in life increases carbohydrate intake, thereby boosting insulin
secretion and causing metabolic programming that in turn,
predisposes the child to obesity later in life.”
For more than 20 years, Patel and his UB colleagues have studied
how the increased intake of carbohydrate-enriched calories just
after birth can program individuals to overeat.
For their rat model of obesity, the UB researchers administered
to newborn rat pups special milk formulas they developed that are
either similar to rat milk in composition, (higher in fat-derived
calories) or enriched with carbohydrate-derived calories.
“These pups who were fed a high-carbohydrate milk formula
are getting a different kind of nourishment than they normally
would,” explains Patel, “which metabolically programs
them to develop hyperinsulinemia, a precursor for obesity and type
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
“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
“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
obesity later in life, he says that parents should follow the
American Academy of Pediatric guidelines, which state that solid
foods should not be given before a baby is 4-6 months old.
Patel adds that this study involved only moderate caloric
restriction; he and his colleagues would like to study whether or
not more severe caloric restriction for a limited period can result
in true metabolic reprogramming to normal metabolic phenotype.
Co-authors with Patel are Malathi Srinivasan, PhD, research
assistant professor and Saleh Mahmood, PhD, post-doctoral
associate, both in the UB Department of Biochemistry.
The work was supported by the National Institute for Diabetes
and Digestive and Kidney Diseases.