Other taxes try to change behaviour  Taxes that try to change people’s behaviour on things that are not liked have been used since the 16th century, and are commonly applied to alcohol, smoking and gambling.  In the US, when cigarette prices went up 4%, use dropped by 10% [11]. As this worked with tobacco, which creates similar health problems to obesity, this tried and tested strategy can work.  Research has shown that when the price of unhealthy food goes up, people eat less of it [12]. A fat tax would make people healthier.