Good Fat, Bad Fat

There is so much talk about fat these days.  Hardly a day goes buy when we’re not bombarded with news headlines and statistics such as these:

  • Childhood obesity rates have more than tripled in the past 30 years
  • More than 155 million children worldwide are now considered obsese
  • 70% of overweight youth will remain obese in adulthood
  • An overweight individual carries an increased chance of diabetes, cardiovascular disease, bone and joint problems, and even cancer
  • In the US, additional medical spending due to obesity related issues is $190 billion a year (>more than 20% of total health care expenditure)

But as these statistics grow, so does the confusion.  especially when it comes to good and bad fats.

When it comes to the dietary stuff, monounsaturated fats and polyunsaturated fats are the good fats because of their overall impact on your heart, cholesterol, and overall health.  Conversely, saturated fats and trans fats are known as the “bad fats” because they increase your risk of disease and elevate cholesterol.

And in case that’s not clear, appearance-wise, saturated fats and trans fats tend to be solid at room temperature (think of butter or stick margarine), while monounsaturated and polyunsaturated fats tend to be liquid (think of olive or corn oil).

Now we’ve got that straight, we also have to consider good and bad body fat.

Essentially there are two types of fat in the human body: white fat, which stores calories and can lead to weight gain, and brown fat which burns calories and generates heat in the process.

But to most of us, fat is unfortunately just fat. Although looking in the mirror might suggest we should shed a few pounds it’s not able to tell us if our problem is the good or bad stuff.

But now in an effort to tackle the global obesity epidemic, scientists at the University of Nottingham, UK have identified a technique to distinguish between the fat types. The non-invasive method uses a thermal imaging camera.  And because brown fat produces 300 times more heat than any other tissue type, heat-sensitive technology can not only identify it, but can also measure how much heat it is producing.

By using the new technique on children as well as adults, the researchers demonstrated that children have larger stores of brown fat and produce heat much more rapidly than adults. Potentially the more brown fat you have or the more active your brown fat is, the more heat you produce  and as a result you might be less likely to lay down excess food as white fat.

Study lead Michael Symonds, Professor of Developmental Physiology in the School of Clinical Sciences at the University of Nottingham, hopes that with these insights, they can learn how to make brown fat more active.

Another of the investigators, Dr Helen Budge said: “Brown fat does appear to be present in higher amounts in larger people than in people of lower body weight, but we think the key difference is in how active it is from person to person.The reason this is exciting is that if you “switch on” brown fat and it uses up energy, then potentially that is one way of controlling body weight.”

It’s long been known that activities such as weightlifting can boost fat-burning capabilities by increasing metabolic rate through lean muscle mass creation.  What if fat could be harnessed in the same way? Knowing what foods to eat to increase energy expenditure from brown fat, coupled with an active lifestyle could help more obese children and adults find a healthy weight.  The results could increase the overall health of a nation by decreasing risk factors for disease and reducing costs associated with obesity.

Further studies of how brown fat responds to different food groups could enable food manufacturers to include a new category of health advice – thermogenic potential – on food packaging. Whereas today we probably look at calorie content or carb content, a thermogenic index on food labels could show whether that product would increase or decrease heat production within brown fat…in other words whether it would speed up or slow down the amount of calories we burn.

Now that really would be useful.