Wednesday, 25 April 2012

Understanding obesity

As a nutritional therapist I find that I often meet naturally thin people who are very unsympathetic to obese people and often can't understand why they don't just eat less food and go for a jog to lose weight!

I was at a seminar this evening on the obesity epidemic in the developed world which actually covered this topic extremely well so I thought I'd share the science and hopefully enlighten a few of you as to the plight of the overweight individual.

Very slim people, who can eat whatever they want without gaining weight, generally don't have proper nutrient absorption so this is not an optimal state. In the days of the cave man these people wouldn't have survived due to the shortage of available food.

We are infact designed to be very economical with our calories so with the current abundance of food it is very easy to over-eat, and therefore gain weight.

Secondly, a sedentary lifestyle is self-perpetuating on a motivational level which means if you are over-weight, and in particular have central obesity around your tummy, then you will have a larger appetite and a lower neurological impulse to exercise than a healthy person.

But surely exercising is just a case of will power?

Not so, the motivation to get up out of your chair and move around is a neurological pathway, you may be lying around on the sofa feeling apathetic, but once you get hungry this dopamine pathway will kick in and you will be motivated to get up and go to the fridge. However the more fat you have around the middle the less active this spontaneous exercise pathway is, so overweight people are naturally less motivated to exercise than slim people. Overtime these pathways can atrophy making it even harder to produce a motivational response to a physiological need.

The other problem is that the more sedentary you are the more insulin and leptin resistant you become, which means your ability to burn fat for energy becomes impaired. As a result you can be over-weight and sedentary but still have a huge appetite as your body can't access any of your fat stores for energy. A very determined overweight dieter can get themselves to a point where they are eating less than 1000 calories a day and yet still can't burn fat for energy (they will just feel extremely tired and not lose weight).

So what's the way out of this vicious cycle?

Well I think that's enough science talk for one blog ... So you'll have to wait til tomorrow for the answer!

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