What are Fat Cells (Adipocytes)? The Definition and Complete Guide

Many people assume that fat in the body is an enemy, but it’s actually the opposite. Without fat we would freeze, our body would not be able to function properly nor would we have an immune system. Fat is essential for holding onto critical nutrients, helps protect the body, keeps it insulated and enables the membranes of cells to work in various ways. 

To make the fat in our body useful, we need fat cells to optimise its benefits. Fat cells, also known as adipocytes, are the cells in the body that compose adipose tissue which store energy as fat. Energy from fat cells is essential for simple bodily functions by transmitting messages through the body, they also help mobilise and maintain energy and help store calories as lipids.

Excess fat can lead to obesity related health conditions and in order to inhibit too much fat or if you wish to shed fat, it is important to understand what fat cells are, how they work and why they can be good for you and your health. Find out more here in our complete guide:

What are fat cells?

Fat cells are scientifically known as adipocytes. They are cells that are made up of adipose tissue, which is essential for insulating the body and storing energy as fat. Adipose tissue is located just underneath the skin, around internal organs, in bone marrow and around the muscles and breasts. This tissue works as a cushion for all of these essential body parts and is where the fat cells are stored.

Adipocytes may seem like small sacks of dull energy, but they are in fact very important and beneficial for many things. They can help regulate hormones and nutrients, help with reproduction and balance blood pressure and blood sugar levels. 

There are two types of adipose tissue, white and brown. In those white and brown tissues, three types of fat cells exist, white, brown and marrow fat cells.

White fat cells, also known as unilocular cells, are primarily made up of triglycerides and cholesterol esters. They contain a single droplet of lipid and are the cells which store readily available reserve energy. They are typically found between the skin and abdomen area. 

Brown fat cells, also known as multilocular cells, are made up of multiple small droplets of lipid with a high iron content, which gives them their brown colour. The main function of brown fat cells is to turn energy from food into body heat. Brown fat cells are found mostly around the neck.

Marrow fat cells, also known as unilocular cells, are useful for losing and gaining weight. Scientists found that bone marrow also contains fat-storing cells which help bone density increase or decrease with weight and exercise. More research suggests that the marrow fat cells are found around much of the body’s cartilage and bones in the body to help with bone metabolism to inhibit inflammation. 

With that information in mind, you may be wondering exactly how fat cells work:

How do fat cells work?

Our body needs fat. Fat cells are convenient as they are small spaces in which fat can be stored and later used as energy. As well as being an energy source, fat cells help with nerve development and function, develop hormone transmissions, insulate the body and cushion internal organs. 

The fat that we eat is actually a chain of hydrogen and carbon which is attached to a sugar alcohol molecule. This chain is broken down by the body which is how fat releases into the body as an energy source. Fatty acids typically provide nine calories per gram. Whereas carbohydrates and proteins offer four calories per gram. 

The more processed fatty foods the body consumes influences weight gain. The way this works is by the body holding onto the extra lipids that we do not use from fat cells. When they are stored, it makes the fat cells grow in size. Also we lose the extra lipids, the cells shrink and we lose weight but the cells never disappear. 

Fat cells produce a chemical called leptin, which is a hormone that sends signals to the brain to make us stop eating. Therefore, as fat cells shrink they produce less leptin, which sends less signals to stop eating and may result in wanting to eat more.

The most effective way to burn fat is through exercise. There are a multitude of fat burning exercise routines such as high intensity training, walking, cycling and cardio activities. When fat is burned, that is when you lose weight. After the body uses all of the energy from the glucose in carbohydrates in the body, the body will start to burn fat. The fat cells will shrink in size but will continue to be used as fuel as they never disappear. The fat cells are refuelled with food consumption. 

There are many foods, medicines and supplements that work to burn fat. The best foods to consume for fat burning are fatty fish, coffee, eggs, bananas, avocados, yoghurt, berries and citrus fruits. Alternatively, there are medications or supplements you can take to encourage fat burning. Supplements are typically safer and more effective due to the use of natural ingredients.

=> Read more about fat burning supplements on our Raspberry Ketone guide.

Fat cells provide the body with many health benefits, mainly from the white fat cells.

White fat cells are the most active of them all for providing health benefits. As well as being the main energy source, white fat cells also help regulate blood sugar levels. They extract excess sugar from the bloodstream in response to any sugar secreted by insulin. If a body contains too much or too little fat, then the response to extracting sugar from the bloodstream becomes interrupted. Adipocytes also break down and decrease blood sugar by releasing proteins.

Another benefit of adipocytes is that they help build, maintain and function the immune system. They secrete cytokines which are chemicals which help inflammation. Promoting inflammation is important for chronic diseases as much as it is for boosting the immune system for fighting off illnesses such as common colds and viral infections

You may be wondering what a fat cell is exactly made up of to understand more on how it works and functions:

Composition of a fat cell

Under a microscope adipocytes look like bulbous spheres. Like most other cells, they have a nucleus and a cell membrane. There is a small part of each cell that is composed of stored triglycerides. 

Human triglycerides look similar to olive oil and other oils which come from plants. They have the same yellow colour, same density and chemical formula. Not all adipocytes are the same but most are white fat cells, which are made up the way as described and are the cells that provide and release energy.

Studies demonstrate how the white fat cells, which store the energy from foods, grow in size after eating and decrease when fat from the cell is used as energy.

Let’s talk about body fat basics in a full breakdown:

Body fat basics: the full breakdown

An interesting study in 2008 found that humans maintain the same fat cell count throughout our lives, regardless if we gain or lose weight over time. Up until the age of 20, the body produces more and more fat cells each year. After this age, fat cells can start to die off due to weight loss and fat burning exercises. However, fat cells can increase quicker than they die off, so it is important to know that fat burning is recommended to maintain a healthy balance of fat levels.

Body fat percentage is good to keep an eye on. For a male, body fat percentage that exceeds 25% is considered to be overweight and for women, body fat of over 30% is a signal of being overweight and is understood as a health hazard. When a person’s body fat percentage exceeds the recommended level, this can cause fat to store in the upper body close to organs, which can cause detrimental issues to health. A myriad of issues can develop from excess fat such as diabetes, cancer and heart disease. 

To determine whether you are over or underweight, the most effective test is BMI. Body mass index (BMI) readings can tell a person if their body percentage is too high, low or just right depending on your age, height and gender. 

Fat placement differs between genders. For men, fat is typically stored around the torso and abdomen and for women, fat is stored generally around the thighs and hips. The location of fat between genders is due to the production and release of different hormones in the body, estrogen and testosterone. 

Fat cells begin to develop in a baby when a woman is pregnant, typically around the third trimester. Fat cells then increase throughout childhood and develop more during puberty, which is where the fat placement takes place. The release of hormones for males and females determines where fat will typically be stored. Once this happens, fat cells will no longer increase but instead they will grow in size when the person gains or loses weight.

Body fat is important to regulate body temperature, cushioning organs, and providing the body with a source of energy. To find out more on how fat cells enter the body so you can understand the process and benefits, here is more:

How do fat cells enter the body?

Fat cells enter the body through the food that we eat. When you eat food that contains fat, mainly foods high in triglycerides, that food is passed through the stomach into the intestines. The large droplets of fat mix with bile salts from the gallbladder and emulsifies, which then turns the large droplets into small droplets and releases throughout the body, increasing the fat’s surface area. 

These small droplets are known as micelles, which are further broken down by lipases, enzymes released by the pancreas, which turns the fat into glycerol and fatty acids. The glycerol and fatty acids components are then absorbed into the cells. Once absorbed, proteins called chylomicrons coat the components and to help them dissolve easier in water. This process allows the fatty acids and glycerols pass through the lymphatic system and eventually into the bloodstream, to be used as energy.

The reason fat is broken down into glycerol and fatty acids is because the fat is too big to be absorbed into the bloodstream. The brown fat cells, which produce heat, are what help break down the fat. The process cycles with fat burning and food consumption. 

Here is more on how to maintain healthy body fat and fat cells:

How to maintain healthy body fat

Fat cells are maintained through the food you eat and the exercise you partake in. Regular consumption of food and daily exercise helps the fat cells cycle in a healthy way. Certain foods can encourage the fat cells to increase and cause weight gain overtime, but with the right foods, you can maintain weight and healthy sized fat cells.

It is important to keep up a healthy balanced diet if you wish to have a healthy body fat percentage. Excess or limited body fat can cause health conditions which if left untreated, can have significant consequences. Therefore, eating the right foods, partaking is regular fat burning activities and understanding how to maintain a healthy body fat percentage is key. 

Starting with food, here are the tops foods for a balanced diet that encourage fat burning:

  • Fatty fish 
  • Avocados
  • Bananas
  • Dark berries
  • Green tea
  • Coffee
  • Eggs
  • Citrus fruit
  • Grains
  • Low-fat dairy 
  • Spinach

Read more about these foods and their fat burning benefits here

Food is not the only way to maintain a healthy body fat percentage and keep up the essential cycle of fat cells. Although it plays a big part, food is what provides the body with fat. In order to burn it effectively, you can eat fat burning foods and/or partake in fat burning exercise. Regular exercise helps burn fat that is consumed. The best fat burning activities are:

  • Running
  • Jogging
  • Walking
  • High intensity interval training
  • Weight lifting
  • Yoga
  • Swimming
  • Pilates 

Keeping up a healthy cycle of food and exercise will encourage your body to regularly burn fat, even whilst resting. This will help maintain a healthy body fat percentage and keep up the cycle of fat cells. 

If you have any unanswered questions or concerns, here are some frequently asked questions that may provide you with what you are looking for:


Do you pee out fat cells?

The body disposes fat through two metabolic processes. You can either sweat fat cells out or pass through fat cells through urination. Research states that around 16 percent of fat is released through water – perspiration and urination – the rest is breathed out as carbon dioxide. 

What food kills fat cells?

There are a few foods that work to burn/kill fat cells, especially fat around the stomach. This includes cinnamon, chilli, fish, meat and water. All of which contains chemicals that work to break down fat quicker than other foods. 

Do fat cells fill with water?

Many dieters claim that when you burn fat, the fat that is left feels jiggly. This is popular with the keto diet and is commonly known as the whoosh effect. It is where people assume that their fat cells fill with water, as they have no triglycerides from food to fill them. However, scientists suggest that cells filling with water is a myth.

How can you tell if you are losing fat?

The most effective way to assess if you are losing fat is through examination. The quickest way is to measure and track the circumference of your body parts – stomach, hips, arm, legs and neck. A decrease in circumference will signify weight loss and fat loss.

If the measurements do not show any progress, this could be because of exercise and the fat being replaced with muscle. Therefore, another method is to measure your BMI which tells you your body fat percentage. 

How can I reduce fat in 15 days?

Whilst fast fat loss is not recommended and it is hard to maintain, it can be done. Consumption of the right foods (proteins, healthy fats, minimal carbohydrates and water) combined with regular exercise (especially fat burning exercise) will result in fat loss. Maintain the routine to see more fat loss. 

How do you flush out fat?

The most effective way to flush out fat is by increasing your water intake. Drinking water helps flush out toxins in the body, and it can also increase your metabolic rate. This will promote fast fat burning. 

How do I stop my body from storing fat?

It is not possible to stop your body from storing fat, as fat needs to be stored in order to provide your body with energy. However, to decrease how much it stores several things can be recommended. Regular exercise, high protein foods, healthy fats and fibers, good sleep quality and lots of water can help promote fat burning. These steps must be maintained to keep up regular fat burning. 

With all of this information in mind, let us tell you our final thoughts:


People need to understand that fat is not the enemy, and we hope we have encouraged you to realise that. Fat cells are essential for providing the body with energy and consumption of the right foods helps maintain the fat burning process.

Men and women store fat differently and it is important to understand that and know why. The chemicals inside the body that breakdown fat work alongside hormones and signal the placement of where the fat should be stored. 

Fat is an essential part of a healthy body and is not there to just provide energy and insulation, fat can also help inhibit health conditions if maintained at a healthy level.

In order to keep your body fat percentage in check, it is advised to regularly track it with measuring your body part circumferences or test your body mass index (BMI). Consumption of balanced foods and regular exercise are the best two lifestyle choices for a healthier body fat percentage and a healthier body overall.

If you have any comments or more questions, please share them with us.

Leave a Comment

Your email address will not be published. Required fields are marked *