Babies are born all squidgy and cuddly and it’s their extra fat that makes them so. But, that baby fat isn’t the same as our excess fat, because not all fat is created equal. Much of a baby’s fat is special and it could be the key to adults becoming calorie-burning machines.
What would we do if we couldn’t shiver? . . . . We’d probably get really cold!
And this is why babies have a special kind of fat – because they can’t shiver. Not all fat is created the same, we have two different types of it – white fat and brown fat.
The fat we call white, even though it’s actually yellow, is what we all think of when we talk about fat in the body. It’s the stuff we consider bad and which collects around midriffs, thighs and bums. It stores calories and can be stubborn to reduce or remove.
The other type of fat – the brown stuff, is medically known as brown adipose tissue and scientists have known about it for decades. Unlike its white counterpart, brown fat actually burns excess energy to produce heat. But sadly, it’s something that is in short supply in adults.
Newborns, on the other hand, have an amazing source of brown fat. At birth, brown fat makes up about 5% of a baby’s total weight. Babies store brown fat in little pockets, mostly along and between their shoulder blades. The purpose of these stores is to protect babies from the cold, because they are far more vulnerable than adults and older children to the dangers of cold exposure.
Adults and older children shiver when they get cold. The rapid expansion and contraction of the muscles, that shivering produces, generates heat. Young babies don’t have the ability to shiver and generate heat. This doesn’t mean you’ll never see a baby shudder – it’s just it’s not to generate warmth. Their inability to shiver and efficiently thermoregulate, combined with the added fact that they lose body heat at a more rapid rate, means that parents should be far more vigilant to monitor and control a baby’s temperature.
Brown fat is chock full of little energy factories called mitochondria. In fact, brown fat cells have a higher density of mitochondria than perhaps any other tissue on the body. Mitochondria are the very powerhouses in our cells that convert the food we eat into energy that runs a range of biological processes. Mitochondria are also critical to cells for a host of other important tasks and, in some way, just about every cellular process is linked to mitochondria.
Mitochondria are brownish-red in appearance, mainly due to their iron content – but may also be so due to vitamins B2, B6, B12 and pigmented flavins. Mitochondria also require a large amount of oxygen from the blood, so brown fat also has a greater capillary density. Together, these two things contribute to the brown appearance of brown fat.
Brown fat is activated when it becomes cold. The mitochondria turn glucose, fat and other nutrients into energy that brown fat cells can use, but they’re not very efficient at doing so. It’s this inefficiency that makes them so valuable. Instead of breaking down all of its food into energy for the cell to use, it leaks out most of that energy in the form of heat.
This is why babies are born with an ample supply of brown fat. To help combat their heightened risk of cold exposure by helping maintain a baby’s core temperature. The brown fat supplies are burnt up in a process called thermogenesis that helps warm a baby when they get cold. This is the same process that hibernating animals use to keep warm in the winter.
Because of this, until recently, it was thought that brown fat stores diminish with age as they become less physiologically important. However, brown fat has been touted as being a possible key to weight loss that stays off.
The vast majority of weight loss protocols call for calorie restriction – which means eating less. But, the studies into brown fat are showing that it’s a hungry little calorie burner and that just 75 grams of the brown stuff could burn up to 500 calories a day!
It’s not entirely clear when we gain the ability to shiver. If we need adequate muscle control to shiver, it could manifest at very different times dependant on each child – think about the variance in abilities to walk. Walking can occur as early as 6 months and for some as late as 2 years. We could, therefore, assume that shivering would develop in a similar fashion.
With brown fat being so great in aiding calorie burning, you may be wondering how you can increase your own. We were! There are a couple of things you can do – cold exposure and exercise. Expose your self to the cold, from ice baths and cold showers to turning your thermostat down a few degrees. This may help recruit more brown fat cells. It has been shown that when you exercise regularly you produce more of a protein called irisin. Studies have suggested that Irisin may help transform white fat into brown.
So get cold and exercise regularly, and you may just turn your white fat into brown fat and become a calorie burning machine!