Bad fat – good fat?
What percentage body fat do we need?

Bad Fat seems to be what immediately comes to mind because 'fat’ is a word that evokes strong feelings. One blogger’s words reflect this: “I’d rather be stupid and mean than fat.” Someone replied: "Congratulations, you already are!"

Fat attracts a barrage of criticism but, we need fat in both our food and our bodies.

Good fat and bad fat

2008 Harvard Medical School research reported in the May Edition of Science News on so called ‘bad’ fat had results that surprised even the researchers. Dr. Kahn’s research was done in an effort to find out why fat located in different parts of the body seems to have different risks of metabolic disease such as diabetes. However, to their surprise they found that a certain amount of visceral fat (the fat just under our skin, traditionally thought of as bad fat), helps to regulate blood sugar.

Mice (which admittedly are not the same as humans) were put into two groups with one group having subcutaneous ‘bad’ fat transplanted into their bellies while the others had a sham procedure. Those mice with the fat transplant not only slimmed down after several weeks, but they also showed improved blood sugar and insulin levels compared to the ‘sham’ group.

You can't be blamed for thinking
'Bad Fat'

Given that we are schooled into thinking that all fat is bad fat, the above research may seem like counter intuitive news. However, we need to be careful not to undermine the importance of body fat. Not ALL fat is bad!

Firstly, we all need body fat -– women need higher percentages than men from puberty on. Women with less than 18% body fat are likely to have amenorrhea (cessation of her menstrual cycle): one of the symptoms of anorexia, or even possibly orthorexia.

We need a certain percentage body fat to keep warm – which is why anorexics struggle to stay warm even in warm weather and why their body often compensates by developing fine black bodily hair. Pregnancy is another time when women’s percentage body fat need to increase to between 25-30% and the same applies at menopause. So let’s not forget that you can’t just label all fat as bad fat because it’s essential to our health in many aspects.

Stages of development

But what percentage body fat is considered bad fat and from what point in life? Well, it seems there really isn’t total agreement on this issue.

Apparently babies are born with approximately 14% body fat (most of which is only accrued during the last trimester). And adult obesity is apparently related to premature low weight babies –so in this case a low percentage body fat is apparently bad fat - because even though the babies head circumferences might be the same as if he had been born at full term, he would had insufficient body fat.

Not only would having too little body fat make it difficult for a baby’s body temperature regulation, but for underweight babies, the rapid fat catch-up that then occurs, renders him/her more prone to developing insulin resistance during childhood and a susceptibility to the development of type 2 diabetes later in life.

Girls experience a ‘fat spurt’ that boys don’t at puberty as their body needs approximately 18-22% body fat for their menstrual cycle to begin. Sadly, it’s often the thought that this is bad fat because of an intense fear of fat that when this ‘puppy fat’ spurt occurs, it is often what triggers dieting . However, that’s not bad fat – that’s good fat because it’s all part of a natural process.

And, fat gain at the approach of menopause if often thought of as bad fat. But there is research that believes that women need between 25-30 percentage body fat at this time because it’s protective against osteoporosis. This is one of the bodies natural processes.

But sadly, especially as fat gain around the belly is what usually occurs in peri-menopausal women - they panic, go on diet and mess with their metabolism.

What fat do we need when?

But what percentage of fat is healthy and what isn’t?

Historically carrying some fat was considered to be an important health reserve , then that changed and thin became the new heath standard for what was considered to be healthy.

But, in an enormous study of 1.8 million Norwegians over 10 years, the highest death rate occurred in underweight women, and the lowest mortality rate was amongst those who were approximately 30% overweight. Even women considered ‘morbidly obese’ had lower death rates than the underweight group.

Then, it appears that how much fat is bad fat and how much is good fat also depends on your stage of life.

But with studies like those by Dr. Kahn and a host of other research from around the globe it seems that the jury is still out on exactly how much fat we need to be healthy.

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