ok, so, given that people already contribute to the nhs through taxation, according to their income, what you are proposing is an additional sum on top of this which is based on your lifestyle? Isthis lifestyle generally or are you limiting this top up contribution to being fat?
What about drinkers? Smokers? Drug takers? people who engage in risky hobbies? People in high risk occupations? City dwellers? People who live in high crime areas?
What about social class? That has a proven impact on health, according to statistics? As does mental health.
People on low income it has been argued live a less healthy lifestyle, should this extra charge include a poor people surcharge? If you have less than £x monthly income it is assumed you will be less healthy so you pay £x more?
And will all this be means tested? or proportional to income? Or will it be a flat rate per habit, hobby, figure or lifestyle choice?
How much will it cost to administer such a system? Will it require a whole government department? Will people be subject to annual medical exams and at what cost? Or will we see an insurance style system with everyone getting an individual quote based on their circumstances? If someone lies on their forms and later needs treatment for, say, a smoking related disease when they claimed they didn't smoke, will they be fined? How will money be recovered?
How much money is likely to be saved by introducing such a system, roughly? You know, the savings to the nhs - the cost of administration of such a system?
I assume that you have given it a great deal of thought and I'd be interested to know how you think such a system would work.