People often want to “lose” body fat, but what type of fat and from where you lose it matters – especially when it comes to health. Whilst you can measure body fat levels through body composition measurements, what does this mean for your health? Read on to understand more about what fat you want and what fat you may want to reduce.
Why is fat important?
Fat, otherwise known as adipose tissue, is crucial for life. Necessary levels are also essential for health. Adipose tissue has a host of different functions throughout the body. It is important to note the difference between survival and optimal health and a certain level of body fat is required for optimal health. Additionally, too much fat can be harmful to your health.
Essential fat is necessary for survival and is found throughout the body – in the brain, organs, bone marrow and cells. Some functions of essential fat include: cushioning and protecting organs, providing crucial energy reserves and acting as an insulator.
Healthy levels of body fat are required for the presence of vital chemical substances and messengers throughout the body. For example, the production of a substance named aromatase which is necessary for making and converting sex hormones. Both too little aromatase and too much aromatase can be a factor in hormone imbalances noted in males and females.
A certain level of fat is also necessary to produce a chemical messenger named leptin, which is critical for the regulation of energy levels, body weight and feelings of fullness. Healthy levels of body fat are also essential to produce certain substances that play a key role in immune health (TNF alpha).
Storage fat is also critical for providing a source of energy. Remember that energy is necessary for every single process that takes place in the body and fat is the preferred energy source for lower intensity exercise/movement. Storage fat also influences body shape and size.
Fat can be classified according to the function that it has, as well as where it is stored.
Different fat for different functions
Fat can be classified according to function. There are two main types of fat/adipose tissue, known as white adipose tissue (WAT) and brown adipose tissue (BAT). These two tissue types have different functions:
WAT (white adipose tissue): is the primary site of energy storage. WAT secretes important substances which have hormonal and metabolic roles. These substances contribute to a variety of different functions: the regulation of energy balance, food intake and feelings of fullness, the inflammatory response and generation of sex hormones such as oestrogen. WAT also helps cushion and protect the body, as well as keeping it insulated. It is the predominant type of fat tissue found in subcutaneous and visceral fat – further details of what these are below.
BAT (brown adipose tissue): is responsible for the non-shivering heat production that protects new born babies. It acts as a sink for the uptake of sugar and fat in the blood and generates heat instead of energy – it essentially helps clear fat and prevent excess fat building up, by generating heat rather than energy. It is mostly located in the upper back, around the clavicles and the vertebrae.
FYI: WAT is made up of WAT cells and BAT is made up of BAT cells. However, there are also another group of fat cells called beige or brite adipose cells which are in between WAT and BAT cells. These are found in WAT.
Okay, over with the science, let’s talk about where this fat is stored within your body and why it matters!
Where your fat is stored matters
Fat can also be classified according to where it is stored in the body. The most referred to categories are subcutaneous and visceral fat. However, there are other categories such as epicardial fat, which is the fat stored around the heart – for the purpose of this article we will focus on subcutaneous and visceral fat.
Subcutaneous fat
Subcutaneous fat is found in the spaces between the skin and the muscles, throughout the whole body. In healthy and lean individuals subcutaneous WAT is the most predominant type of fat, making up approx. 80% of all fat tissue. It functions to preserve heat loss, act as a barrier against infection and provide protective cushioning. It can be separated into upper and lower regions and upper subcutaneous WAT is often lumped together with visceral WAT, classified together as abdominal fat.
Visceral Fat
Lean healthy individuals do not have much visceral fat. Visceral fat is predominantly found around the organs in the abdominal area, such as the liver, intestines, and kidneys. The accumulation of visceral fat comes from excess subcutaneous fat which essentially overspills. This type of fat has become dysfunctional and secretes harmful substances that contribute to poor metabolic disease – from inflammation, to elevated levels of insulin and blood fat levels, and heart disease.
How does what fat you have impact your health?
Visceral fat is associated with insulin resistance, predisposition to diabetes, inflammation, high cholesterol, high blood pressure and heart disease. Because this type of fat is dysfunctional, it secretes harmful substances which affect the organs around it. One school of thought with a great deal of research to support it, indicates that visceral fat results in a chronic low grade inflammatory state which contributes to chronic disease throughout the body and has a strong relationship with insulin resistance. In addition to contributing to chronic disease such as type 2 diabetes, cardiovascular disease and non-alcoholic fatty liver disease, a chronic inflammatory state is associated with poor immune health.
Does what fat you have matter more than how much fat you have?
Yes and no!
Yes
“normal” weight individuals who accumulate fat around the middle are likely to suffer from metabolic abnormalities, including increased risk of heart disease. Different ethnicities have differing susceptibility to accumulating fat around the middle – for instance, Asians are particularly prone to accumulate intra-abdominal fat despite being at a “normal” weight. This is why the use of body weight or body mass index (BMI) can often be an ineffective indicator for understanding an individuals health status.
Measuring body composition on the other hand can be a much more valuable tool providing a greater degree of insight into potential metabolic health status. In the case of understanding an individuals metabolic health, waist circumference, waist/hip ratio, weight to height ratio are more informative measurements.
As part of our in-clinic body composition assessments we look at the following areas:
For more information on the body composition testing we offer in clinic, click here. You can also see a sample report by clicking here.
No
Visceral fat tends to be a result of too much subcutaneous fat. Fat (adipose) cells grow either by becoming bigger in size or by becoming increased in number. When they grow in size, they can become dysfunctional –secreting harmful substances and subsequently creating a low grade inflammatory state. It is thought that each individual has a certain amount of fat cells that they can make and that this number will vary according to you as an individual. Nevertheless, if you exceed the amount of energy that you can store (in your number of fat cells), your fat cells have no choice but to expand and overflow, resulting in the development of visceral fat. Therefore, how much fat you have does matter, because if you have too much fat for you as an individual, then you will be likely to gain visceral fat which is particularly harmful and is associated with the onset of poor metabolic health!
How do I know if I have healthy levels of fat?
By utilising feedback from the body:
Body fat levels that are too high fat levels may be associated with: low energy levels, dysregulated appetite, ache and pain in the joints, discomfort when moving, increased state of inflammation, reduced libido, heavier menstrual cycle, more difficulty sleeping (association with sleep apnoea) and impaired or imbalanced immunity to name a few.
Body fat levels that are too low may be associated with: fatigue, poor concentration, low energy levels, reduced libido, frequently becoming ill, slow recovery, reduced levels of performance, feeling cold, either increased or reduced appetite, irregular or absent menstrual cycles.
However, sometimes the body can take a while before it manifests symptoms and therefore checking in with a Nutritionist or Health coach to share your thoughts, may be helpful. If you have already had some feedback from your physician or are concerned about your weight, then opting for body composition measurements can also provide you with some further objective feedback to provide greater insight onto your fat levels. It would be advisable to pursue body composition measurements from a trained practitioner to ensure appropriate and reliable measurements are taken and that both context and relevant advice is provided to support the results meaningfully.
In clinic we use SECA mBCA BIA measurements to accurately assess body composition. For more information on the body composition assessment we offer in clinic and to schedule an appointment, please visit our main body composition testing page.
Equally, if you are interested in working with one of our Nutritionists and Health coaches to support you with changes that improve your body composition and overall metabolic health, you can complete the consultation enquiry form at the base of this page. As part of any in person consultation with one of our team, you will be able to include the body composition assessment as part of that service.
Key takeaways:
Body fat is essential for life and optimal health: body fat serves multiple purposes – from the cushioning of organs, to being an important source of energy and being involved in the production of many critical substances involved in immune, metabolic, and reproductive health.
Where you store your fat matters: visceral fat, stored around the organs in the middle of the body, is associated with poor metabolic health – for example, increased risk of cardiovascular disease, type 2 diabetes and insulin resistance.
Your body fat levels need to be optimal for you: whilst too much fat is most definitely dangerous, contributing to the development of visceral fat and potential poor metabolic health, too little fat is associated with a host of health risks – from reduced immune health, libido, to loss of menstrual cycle, to poor bone health, are just a few. Therefore, if you are concerned that you may have too much or too little, it may be worth discussing with your Health coach or physician and / or considering some body composition measurements.
If you are concerned about whether you have healthy levels of fat: you may wish to pursue speaking to a trained healthcare professional and/or gaining further body composition measurements to add insight and provide some objective data that allows you to set realistic goals and encourage change.
References
- Chait et al. (2020). Adipose distribution, inflammation and its metabolic consequences, including diabetes and cardiovascular disease
- https://www.frontiersin.org/articles/10.3389/fcvm.2020.00022/full#h9
- Ikeda et al. (2018). The common and district features of brown and beige adipocytes.
- https://www.cell.com/trends/endocrinology-metabolism/fulltext/S1043-2760(18)30001-8
