Having low amounts of body fat is desirable for so many people, however the human body has evolved to utilise body fat for biological and physiological purposes. Fat is natural. Having body fat is healthy. Fat is an object not a feeling.
Humans have survived for thousands of years due to body fat. Body fat acts as an energy reserve. The body stores fat in adipose tissue at times when energy (from food) is plentiful and draws on these stores in times of energy deficiency and famine. Looking back in time when humans were hunter-gathers, a successful hunt would mean a plentiful energy intake. When excess energy was consumed it would be stored as body fat. If the hunt was unsuccessful and limited energy was consumed, body fat stores would be tapped into to keep humans alive. The storage of fat also acts as protection for vital organs, such as pancreas, kidneys, liver and heart. The storage of fat in the liver, enables a storage reserve of vitamins A, D, E and K. These fat-soluble vitamins are involved in life-saving body functions such as eyesight, bone formation and blood clotting.
As well as energy reserves, fat acts as an insulator, keeping the body at a preferred temperature range of 36.5- 37.5 degrees Celsius. In temperatures below this range, body fat helps to shield out lower temperatures, whilst keeping warmth in.
Fat also serves structural purposes. Fats or their medical term; phospholipids are used in cell walls to keep cells fluid and lubricated. Fat is also a structural component of the nervous system. In fact, the brain is made of 60% fat. Brain fat cannot be made from other building blocks therefore consuming dietary fat, particularly omega 3 fatty acidsare important for brain health. Fat is also used within the body to coat nerves; myelin sheaths are the outer coating of the nerve which protect the nerve signals from becoming miss matched.
Fat is involved in hormone production too, in particular, fat is the foundation of steroid and sex hormones synthesis, which under pins reproduction. When body fat levels are very low, particularly in females this can have knock-on effects with fertility and bone health. Naturally, women have higher body fat percentages due to their ability to bare offspring. Women naturally have more body fat due to their ability to breastfeed,drawing on body fat stores to support breast milk production. The fat content of human breast milk is 3-5%, which comes from the mother’s stores.
Our body likes to hold onto fat as it is integral is many physiological functions including ensuring the longevity of the human species. Healthy body fat percentages for males is 18-14% and females 25-31%. The body has cleverly evolved to use hormones to ensure body fat is in plentiful supply, such are ghrelin and leptin. Ghrelin is a hormone that tells our brain we are hungry and when to eat, whereas leptin is the hormone which gauges body fat levels. So as much the wish body fat didn’t exist, if we didn’t have body fat the human race wouldn’t exist.
Alyce Rees – Accredited Practising Dietitian/ Personal Trainer
Food in Action – Dolphins Health Precinct, Redcliffe
Phone: 07 3880 3729
Email: [email protected]