The temperature has dropped and winter is looming but it’s time to turn down the central heating and leave your coat at home. Research into brown adipose tissue (BAT) is growing as a means of managing weight and preventing weight related disorders such as type 2 diabetes. There is a growing understanding that BAT is an important endocrine organ with multiple metabolic functions. Brown adipose tissue, in contrast to white fat, can dissipate significant amounts of energy through heat production (thermogenesis). This process can be activated by certain stimuli, such as cold exposure and stress hormones.
What is BAT?
The function of brown adipose tissue is to transfer energy from the food we eat into heat. This helps burn calories and aids weight loss in two ways: it takes energy to produce heat and takes away energy from other fat cells stopping fat accumulation.
In addition, brown fat activation seems to have positive effects on metabolic processes, such as balancing blood sugar and controlling appetite-boosting hormones.
When we are born, we have a large amount of BAT, which has the ability to burn more energy (calories) to be used for body heat. During this process, the body’s internal temperature increases and helps reduce other fat deposits made of white fat. Studies have shown that brown fat can burn up to five times more calories than other types of body fat.
One of the reasons babies have such a high percentage of BAT is because they can’t shiver in response to being cold to regulate their body temperature, instead they must rely on brown fat to turn up their body heat. Young children retain their BAT, but as we get older levels begin to decline. The extent of the decline is influenced by genes and changes in hormones, with some lucky individuals holding on to more of their BAT well into adulthood.
How do brown fat and white fat differ?
- White fat: White fat is the type of fat that most of us try to avoid accumulating. White fat cells store energy in the form of a single large, oily droplet. White fat does help us to regulate our temperature by insulating organs, but it does little to burn calories like brown fat does. White fat is found below the skin (subcutaneous) and around the organs (visceral fat, which can be especially dangerous) and accumulates from a surplus of calories. White fat has an effect on hormone production and hunger levels, and in healthy, non-overweight humans, it can comprise up to 20 percent of body weight in men and 25 percent in women.
- Brown fat: Brown fat cells contain mitochondria and are made of a larger number of oily droplets, which are also smaller than those that make up white fat. Brown fat seems to act similarly to muscle tissue in many ways, and actually uses white fat for fuel at times. Within brown fat’s mitochondria (which are often nicknamed the “power house” of cells), heat is able to be generated that helps regulate the body’s internal temperature in response to the changing environment outside.
Benefits of BAT
The creation of body heat takes a lot of energy and this calls upon using the body’s excess fat stores for fuel. Brown fat is responsible for “thermoregulatory thermogenesis,” in other words regulation of temperature without shivering (or nonshivering thermogenesis). It also helps release the hormone norepinephrine when we are very cold in order to let us know we are uncomfortable and potentially in danger, so we need more heat.
Studies have shown that by increasing brown fat purposefully in obese or overweight adults, excess stores of white fat might be reduced naturally. Brown fat has also been shown to be one of the tissues in the adult body that can be stimulated to use the highest amounts of glucose, helping to control blood sugar levels.
Rather than slavishly dieting, it’s time to consider how your lifestyle habits play a role in building brown fat and controlling your weight.
5 tips to increase brown fat
Many experts believe that holding onto the existing brown fat we had during our younger years, as opposed to building up higher stores once we are older, is likely the best way to get the most benefits from brown fat. This means that the following good habits are important to develop in childhood. However, it’s still not too late to make some changes:
1. Turn down the temperature
Keep your home at a lower temperature, go outside as much as possible, especially when it’s cold and consider taking a cold shower every day. This will activate brown fat and help burn hundreds of calories every day.
One Japanese study found that when adult men with low brown fat stores sat in a room chilled to 17C for two hours a day over the course of six weeks, they burned between 108–289 extra calories in the cold compared with sitting in normal indoor temperatures.
Even more interesting is that at first they were burning on the lower end (around 108 extra calories) during the two hours, but after six weeks they were up to burning 289 extra calories on average in the cold, suggesting that a build-up of cold tolerance can activate certain genes which boosts brown fat.
Exercising outside and activities like cold water swimming have been shown to increase activity of brown fat and have a positive effect on the release of hormones that control body fat and lean muscle development.
3. Follow your body’s hunger and fullness signals
The neurons in our brain that regulate levels of hunger hormones play a part in maintaining brown fat. These neurons that control our appetite can also help encourage white fat to act more like brown fat. However, the extent to which this happens depends on how we respond to their signals — specifically if we eat enough to feel satisfied, but don’t overeat and consume more than we really need.
Eating enough to feel comfortably satisfied prompts actions of these neurons and boosts brown fat effects. Over-consumption of calories confuses neurons that control hunger hormones and leads to extra white fat storage. Conversely, undereating can slow down brown fat activation.
4. Get a good night’s sleep
Research shows that melatonin can activate brown fat. One study showed that higher levels of melatonin from having deeper and longer sleep, lowered weight independently of food intake and activity.
Instead of relying on melatonin supplements to boost these effects, try to improve your ability to produce more melatonin naturally by focusing on regulating your circadian rhythm. The best way to do this is to avoid “blue light” exposure from electronic devices before bed, try to go to sleep and wake up around the same times every day, and to get more sunlight exposure during the daytime.
5. Learn to manage stress
Stress promotes the storage of dangerous fat (like visceral fat that surrounds our internal organs) and also makes it hard to eat according to your body’s hunger signals.
Learning to manage stress can help you sleep better, motivate you to exercise regularly, eat well and help prevent comfort eating. These are all factors that have the biggest impact on your ability to activate brown fat.