Facts about fat!
It’s not uncommon that as individuals we want to hold less fat mass on our bodies. However, most of the time when we think of losing fat, we think of just saying goodbye to that ‘beer belly’ or that unwanted fat on our legs – but what if there’s more to fat than meets the eye? How much is too much? How little, is too little? Here’s what you need to know!
There are in fact six different types of fat in our bodies. These are broken into two categories: ‘essential fats’ and ‘storage fat’.
Essential fat is the fat that your body requires to live, and is found in bone marrow, organ membranes, nerve membranes and muscles. Essential fat helps to regulate hormones (particularly fertility hormones), cell structure, body temperature and vitamin absorption. Essential fat is around 3% of total body mass for men and 12% of total body mass for females. Females require more essential fat due to childbearing and hormonal functions. Not having enough essential fat in our body can lead to physiological impairment, such as the body’s ability to regulate blood sugar, delivery of vitamins to organs and the ability for the reproductive system to function. Furthermore, bone health is also dependant on circulating levels of estrogen, which can be disrupted with too little fat mass. An indication of not having enough ‘essential fat’ can be having low energy levels, mood swings, brain fog, struggling to stay warm, or in women – irregular periods or amenorrhea.
Storage fat is not required for normal physiological function and is stored in the bodies cells as an energy reserve. Storage fat is found on the body as subcutaneous fat and visceral fat.
Subcutaneous fat is the layer of fat directly below our skin and is a combination of white, brown and beige fat. Some subcutaneous fat is healthy, however outside these levels can result in metabolic syndrome and some cancers.
White fat – are white cells which store in the form of triglycerides and are created by consuming too many calories and expending too few calories. They are our largest form of energy reserve. These cells are a major endocrine organ, which produce a form of oestrogen (leptin) which help promote hormonal health and the sensation of ‘feeling full’. However, when the body is consistently faced with high levels of leptin due to excess white fat, the body becomes less sensitive to leptin’s effects (feeling full) resulting in leptin resistance and therefore a cycle of hunger and fat gain. Excess of this type of fat throughout the body is associated with an increase risk of cancer and associated with sleep apnoea.
Brown fat is the opposite to white fat – in that it burns energy (to store heat) rather than storing it. It is usually found in the neck and upper back and is often referred to as the ‘good’ fat. Brown fat can be generated by exercising, getting a high-quality sleep and exposing yourself to the cold regularly (such as lowering the temperature of living/working spaces or exercising outside). Additionally, overeating not only increases the amount of white fat cells, but also results in the inability for brown fat cells to burn calories. In newborns, as much as 5% of their total weight is made up of brown fat and is used as a mechanism for regulating heat. However, as we grow and develop we have other ways of regulating heat (the ability to shiver, having a larger surface area, more muscle mass etc.) and the proportional amount of brown fat we have as adults is significantly reduced.
Beige fat is proposed to be different cells entirely to brown fat, however this has not been well studied and it is unclear if their function differs greatly from brown fat.
Visceral fat is white fat stored in the abdominal cavity around the organs. It is the type of fat that when measured (with a DEXA scan), can give an indication of your risk of chronic disease (heart attack, stroke, type 2 diabetes). Visceral fat secretes a protein which increases resistance to insulin and glucose intolerance. It has also been liked to Alzheimer’s disease and dementia. Interestingly, visceral fat has been shown to be particularly sensitive to inflammatory effects of processed foods – so these should be lessened or eliminated from your regular diet!
B.CLINEXERPHYS, AES, ESSAM
Accredited Exercise Physiologist