Igonrance. It's not fat that makes us fat, it's sugar. Eliminate sugar (i.e. the powdered white stuff that you don't snort, smoke or inject) from your diet and fat more or less doesn't matter.
So a fat tax, on food, is misdirected, You can stay fat on white bread, potatoes, and rice and low fat (but high sugar) icecream easy enough.
A fat tax on people is ridiculous: You are rich and fat, you can afford to pay the tax and live like you always have; you are poor and fat, the tax makes it even harder to buy good quality food (more expensive) because you have even less money, so what do you do? Buy the cheap stuff loaded with sugar (and cheap fats) which just makes you fatter.
Drs who treat obese people will tell you diet has a very low success rate, and it's extremely difficult to get a decent exercise regime going. The best (most reliable) results is surgery: stomach stappling, gastric bypass, that sort of stuff. My friend was about 130Kg (~285lbs) 4 months ago, he's always been an active guy even tried dieting but to no avail. He had the stomach surgery and now he's at about 90kg (~200lbs) after only 4 months.
I say, if we're serious about wanting to reduce the long term health and social costs of obesity, every obese person who wants it (i.e. there should be no coersion) should get stomach surgery at minimal or no cost. They WILL loose a lot of weight. Within the space of about 5 years you'll have a vastly reduced obesity rate with major long term benefits for the individual and society.
Then all that's left is prevention, which is not about taxing food, but educating kids and parents about healthy diet and exercise choices. Which also means health / diet / nutrition experts demonising sugar as much, or moreso than fat.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
