The findings indicated that infant marmosets were more likely to become obese by the age of one if they began eating solid food early. This early life obesity resulted in metabolic damage such as insulin resistance and poor blood sugar control, researchers revealed.
Led by scientists at The University of Texas Health Science Center San Antonio and the Smithsonian Conservation Biology Institute, the research team also showed that marmosets on track for obesity appeared to be more efficient in their feeding behaviour.
"Although all animals consumed the same amount of liquid, the ones taking in more on each lick were the ones that later became obese," said Dr Corinna Ross - lead author of one of the two studies that appear in Obesity.
The increasing prevalence of childhood obesity and the associated risks of adult-type disease among children have led to worldwide concern.
However, it remains unclear how genetic predisposition, environmental exposure to obesogenic food, and developmental programming interact to lead to overweight and obesity.
As a result, Ross and her colleagues suggest that the development of a non-human primate model of obesity, and particularly juvenile obesity, "is an important step to elucidating the factors associated with obesity and evaluating intervention strategies."
Indeed, Dr Suzette Tardif, also involved in the research, commented that due to their small size and early maturation, "we think the marmoset is going to be an exceptionally good model of early life obesity and offers many opportunities to further explore why youngsters become obese and what interventions may work to counteract early life obesity."
In the new studies the research team monitored marmoset infant behaviours seven days a week to precisely document when each infant was weaned and ate its first solid food, said Ross.
In the first study (found here) infant marmosets were then followed for 12 months, while feeding phenotypes were determined. In this study, Ross and her colleagues found that marmosets that were found to be obese at 12 months of age (more than 14% body fat) started consuming solid food sooner.
"These individuals developed stable feeding phenotypes that included being more efficient consumers during liquid intake trials, drinking more grams of diet per contact," said Ross and her team.
"The weaning process appears to be particularly important in the development of feeding phenotypes and the development of juvenile obesity for the marmosets, and thus this is the time that should be focused upon for intervention testing in both nonhuman primates and children."
The second study, led by Dr Michael Power (found here) took these findings one step further by exploring the metabolic consequences of this early life obesity in marmosets - and found that the obese monkeys aged six months already had significantly lower insulin sensitivity than non-obese.
"By 12 months obese subjects also had higher fasting glucose and circulating adiponectin tended to be lower," said the researchers.