Monday, 7 October 2013

Two Types of Obesity (including 'Bad Obesity')

From New Scientist:
  • "It clearly shows that there are two types of obesity, and that bad obesity is characterised by a fatty liver," says twin researcher Tim Spector of Kings College London, author of the book Identically Different: Why you can change your genes. However, what predisposes some individuals to accumulate fat in the liver, and" to grow fewer, larger fat cells remains unclear.
I've mentioned Identically Different before here and here.

I'm not really in to the Sisyphian task of dividing stuff in to simple 'good' and 'bad' categories - and 'bad obesity' stumbles in to that exact same problem.  But it is good to see some issue developing naunce.

It is easy to establish that obeisty is nuanced.  Ask a skeptic 'why do we get hungry' and you'll get talk of an 'energy deficit' and the body requiring to restore its energy levels, of conditioning and hormonal factors.  But here is the kicker - why do the obese get hungry?  I mean clearly the obese do not have a calorie deficit - they are carrying kilograms of energy!  Why can't they access it?

Similar complexity is evident with the obese who are often relatively weight stable despite eating whatever they want.  How is it that for many, their weight gain is slow if at all, despite not watching what they eat?  And yet when they slim down, they cannot sustain the lower body fat levels (despite rigourous dietary control), return to 'normal eating' and rebound quickly to their previous weight where they once again stabilise? 

The critical points are that they can enjoy a stable weight without any requirement to control dietary intake when obese, but are not able to enjoy weight stability in a lean state.  Why?  Similarly why is that rebound so quick?  Why does the weight gain stablise when back to pre-diet weight....almost as if a set point is being defended?

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