how FAT
BABIES develop
HEALTHY ADULT BRAINS
WHAT’S NOT TO LOVE about a fat baby?
Bouncy, bonny babies are adorable. But
that little cherub wasn’t born chubby just
to trigger the human bonding process.
Without that full-body cushion of
subcutaneous fat, the risk of damage to the
rapidly developing brain would be severe. 1
Th e fat-free option would be a high-risk
strategy at any age, but especially for babies.
Humans are the only land mammals
born fat. Even our closest relative, the
chimpanzee, arrives in the world with barely
any body fat. But no other land mammal has
a brain so highly evolved that it must come
equipped with its own fuel supply. 2
Th ere is only one reliable and complete
source of that valuable fat: animal-based food.
Early humans’ switch from a tree-dwelling,
plant-eating existence to a land-based,
omnivorous lifestyle, triggered extraordinary
brain growth.. Th e human brain tripled in
size over a period of 2.6 million years, and
it did so on a diet of meat and fi sh.
Th is rapid growth is paralleled in the
womb. During the fi rst two trimesters of
pregnancy, the fetus is a virtual fat-free
zone, and brain size is the same as other
primates. Th en, during the last trimester,
the brain begins to expand faster than the
rest of the body. 3
Fat is the driver behind this distinctly
human phenomenon. It forms 60 percent
of the dry weight of the brain. All types
of fat are there: saturated, unsaturated,
and cholesterol, with roles involving both
structure and function. Body fat also
provides ketone bodies, a specifi c brain
fuel that is essential for growing babies.
When it comes to brain function, there
are two crucial polyunsaturated fats that
are found exclusively in animal foods.
Th ese are docosahexaenoic acid (DHA,
an omega-3 fat), and arachidonic acid
(AA, an omega-6 fat). Both are highly
concentrated in the brain.
Th ese fats form part of each cell
membrane and control what passes in and
out of each nerve. Th ey are involved in
Subscribe at: PaleoMagOnline.com
By Maria Cross, MSc
communication between nerve cells, the fi ring of neurons,
the regulation of neurotransmitters, and the development of
cognitive skills. During pregnancy, a mother will pass more
DHA and AA to her baby than she stores in her own body.
AA is found abundantly in meat, and DHA abundantly in
seafood and oily fi sh—salmon, mackerel, trout, herring, and
anchovies. Although muscle meat contains only small amounts
of DHA, off al meat—especially brain—is a good source.
Although DHA and AA can both be made from plant
foods, such as nuts and seeds, the conversion rate is low and
unreliable, and that’s if you’re an adult. Babies are unable to
make any DHA or AA from plant sources and are entirely
dependent on a direct supply from their mother’s milk,
formula feed, and weaning food. 4
As well as these polyunsaturated fatty acids, the brain also
requires saturated fat, which forms the cell membrane, and
large amounts of cholesterol. So crucial is cholesterol that the
brain makes its own supply. Cholesterol is often vilifi ed, but it is
in fact a signifi cant component of the brain, which contains 25
percent of the body’s total supply. It is used by every part of the
brain, functioning as an antioxidant, an electrical insulator, and
as “scaff olding” for the network of neurons. 5 No other part of
the body has such a high concentration of cholesterol.
A healthy baby is born with around three months’ store of
DHA and AA. Th is acts as a form of insurance. Th e baby’s
brain weighs 350 grams, on average, and in six months that
will almost double. By the end of the fi rst year, it will have
increased by another 40 percent. Th at’s assuming, of course,
that it has enough fat to fuel this activity. 3
Th ere was a time when eating high-fat diet was a given if
you wanted to survive. Th e preference of our hunter-gatherer
ancestors for large, fatty prey is well documented. Th e period of
our history that saw the greatest burst of brain growth was the
reign of Homo erectus, who appeared about 1.9 million years ago.
Th e archaeological evidence shows that the mighty erectus had
a particular fondness for large, fatty prey, including elephants,
hippos and rhinos. 6 Th ese smart folk knew how to make
sophisticated tools to butcher a carcass effi ciently, and consume
each and every fat-rich organ of their prey. Homo erectus was
strong and big-brained, and survived for 1.5 million years, an
achievement we sapiens are a long way from realizing.
Fast forward to today, and the standard advice of health
experts is eat less fat. Eat less meat. Even give it up entirely.
Th at has been the offi cial advice since the 1960s, when Homo
expertus fi rst emerged, clutching a clipboard and telling us that
for the entire history of humanity we’d been doing it all wrong.
We took the experts at their word. In her book Th e Big Fat
Surprise, Nina Teicholzs says that “By 1995, a survey of about
January 2018 Paleo Magazine Express
15