. What a person does with their own body is not the government's business.
Well it does matter in the rest of the developed world that has socialised health care systems.
For example. Smoking in Australia, although not banned, is now incredibly invonvenient. The goverment banned all advertising; smoking in workplaces, all public enclosed spaces, outdoor eating places, street malls; jacked the price up to $20 a packet; hid the packets under counters; removed all branding from the packets themselves. Why? because the government (ie the tax payer, ie me) bears the burden of providing their health care. The same can be argued for huge serviving of HFCS drinks.
The trick is striking a balance between restricting an activity that reduces your lifespan and costs society $$ vs the individuals freedom.