We’ve all heard that fat isn’t the best thing for our health. Now, don’t get me wrong… I’m not directing this at fat or thin people, but I think everyone would agree that obesity is a health hazard. It leads to a whole range of problems, including diabetes (Type 2), heart diseases, arthritis, hypertension, etc. People resort to various methods, and sometimes extreme measure like starvation, just to knock off a couple pounds. I don’t want to condone or discourage any such behavior. A person’s body is their own and they are free to make their own decisions.
Now hold on your seats… what if I told you that fat could help prevent obesity?
Fat cells are called adipocytes. We all have them. These are specialized cells that operate as our energy reserve – they store energy in the form of fat. Few people know, however, that we have two types of fat cells – white and brown.
Brown Fat vs White Fat
Grab that roll of fat anywhere on your body… that’s your white fat. These are the most abundant type of adipocytes and are present all over our body. They act as a reserve of energy for when we don’t have any energy input. White fat cells are the ones that increase the risk of obesity, and the ones we lovingly refer to as ‘fat’. To get a little more technical, these cells have a single large lipid droplet that pushes the nucleus to the side. They secrete certain enzymes and are called unilocular.
The other type is brown adipose tissue (BAT) or brown fat. These cells are smaller and packed with iron-rich mitochondria. The main function of a mitochondria is to produce energy. This abundance of mitochondria is what gives these cells their brown color. Instead of having a single lipid droplet, they have multiple lipid droplets scattered around the cell. These are multilocular. Although their nucleus is not in the center of the cell, it is also not pushed to the border, as in the case of WAT (white adipose tissue).
What does brown fat do?
Have you ever seen a tiny baby shiver? Or a hibernating animal? No! That’s because they don’t. Shivering is basically a reflex reaction of the body to generate heat. Humans are warm-blooded, which means that we need to maintain our internal body temperature within a specific range. When we get cold, we inevitably shiver. This is called thermogenesis, which is the production of heat. Shivering increases muscle activity, thereby producing heat. Babies, at that age, have not yet developed the mechanism for shivering. Therefore, they stay warm due to the activity of brown fat. WAT produces energy in the form of ATP (adenosine triphosphate). BAT produces heat, instead of producing ATP. This is known as non-shivering thermogenesis.
The mitochondria of brown fat cells express a protein called uncoupling protein UCP-1. This protein helps to dissipate the proton motive force, which is responsible for the generation of cellular ATP. Due to this, the numerous mitochondria generate heat, rather than producing ATP. Whenever the sympathetic nervous system detects that the baby is in a cold environment, it triggers the brown fat cells, which generate heat to keep the baby warm.
Brown fat cells comprise about 5% of a baby’s weight. As the child grows, this amount of brown fat decreases.
Brown fat and Obesity
From what we understand, due to their functioning in babies, brown fat cells are activated by the cold. Studies have proven that the concentration of brown fat cells decreases in individuals who are kept warm. Another thing that activates brown fat cells is overeating! Yes, you read that correctly. This is the body’s mechanism to prevent obesity due to overfeeding. In fact, studies have shown that there is an inverse correlation between the amount of brown fat cells and one’s body mass index. There is a decrease in the number and activity level of BAT with age. This could explain why older people tend to put on weight more easily.
Brown fat cells burn calories to generate heat. This we’ve already established. It also helps in keeping overfeeding-induced obesity at bay. However, can it be used to lose weight without obesity being in the picture? This remains under debate. Higher levels of brown fat cells have been observed in leaner individuals. However, there is no formal proof for this. Supplements may be available in the near future that trigger the increase of brown fat production. However, we must also consider the fact that an abnormal increase will lead to an increase of heat production.
There are certain ways that can, theoretically, increase one’s BAT content naturally. Exposing rodents to cold environments has led to the conversion of white fat to brown fat. Therefore, this could be a potential method. However, rodents and humans function differently, and as yet, no human trial has confirmed this theory. Another thing that supposedly increases brown fat is exercise. Again, there is no formal proof for this, but even the laziest of us will agree that exercise never killed anyone! It has a number of other benefits, including weight loss, so just get up and do it already!
- National Institutes Of Health (NIH) (Link 1)
- National Institutes Of Health (NIH) (Link 2)
- Medical News Today