What Are the Functions of Baby Fat?

Baby fat, often known as brown adipose tissue or brown fat, is prevalent in newborn babies and small children. It serves several key functions in the first year of life, and as more research suggests, possibly well into adulthood.

Brain Development

• There is a clear correlation between baby fat and brain development. According to Stephen C. Cunnane, whose book "Survival of the Fattest: The Key to Human Brain Evolution" analyzed the role of baby fat in brain growth, the large size of the human brain and the rapid pace in which it develops in the first year of life is one of the largest reasons human babies have more fat than other primate babies. Infants need a built-in resource of energy for their expanding brains, and excess baby fat serves that purpose.

Thermoregulation

• One of the other main functions of baby fat is thermoregulation, which maintains a baby's balance between heat loss and heat production. According to Kent B. Whitaker in his book, "Comprehensive Perinatal and Pediatric Respiratory Care," babies rely on fat to produce heat because they do not have shivering reflexes or the ability to generate heat through increased activity. They are also more susceptible to cold than adults because of a higher ratio of body surface to body volume, a higher proportion of head surface area and an underdeveloped nervous system. Baby fat is a large way in which babies are able to regulate their body heat.

Concerns

• While baby fat has its functions, it also raises concerns. Several recent studies have correlated being on the high end of the baby weight chart with increased risks for obesity and weight problems in childhood and adulthood. A study in the Journal of Obesity found that babies six months and younger are 60 times more likely to be overweight than babies at that age were 20 years ago. A Harvard study, published in the journal Pediatrics, found that heavy infants were more likely to have weight issues by the time they were toddlers.

Other Opinions

• Still, the chubby baby is still typically considered the hallmark of health. The Centers for Disease Control (CDC) say that before age three, the weight of the parents is a stronger predictor of weight problems than where an infant places on the growth chart. Other factors, such as a child's diet, physical activity and TV/computer use also have a far greater impact on future weight than their percentage of baby fat or their weight as an infant.

Role in Adults

• Interestingly, baby fat can actually play a positive role in fighting obesity in adults. A recent study published in The New England Journal of Medicine found that brown fat, generally found in babies and children, was actually fairly prevalent in thin, fit adults with healthy blood glucose levels. Heavier adults tended to have higher levels of regular white fat. Researchers say this suggests that small levels of baby fat in adults may have a role in regulating body weight and protect against obesity.