In Integrated Marketing Communications (Social, Ethical, and, Regulatory Aspects of Advertising), Should it be legal to advertise High-in-Fat Foods? Lotteries? Tobacco? Firearms?

http://www.ecc.jp/

It clearly depends on a local market, which is under a certain jurisdiction. For example, in some states or countries they prohibit agressive advertising of tobacco.

You can look up some possible prohibitive regulations in Japan by using "Hourei Data teikyou" system.

Hourei Data teikyou system (Japan's Laws and ordinances: Data search system)

http://law.e-gov.go.jp/cgi-bin/idxsearch.cgi