The New York Times claims that Donald Trump drinks ‘a dozen’ Diet Cokes a day. At 42mg of caffeine per 330ml, what impact, if any, could this have on the President’s health? Jordan Dunbar speaks to experts about the effect caffeine has on your brain and talks to a high profile self-confessed Diet Coke addict in the UK. "Milkshake Duck" is internet slang for an ordinary person who is briefly cheered, but then swiftly turned upon. We explain why an 11 year old boy and his family are the latest victims of this phenomenon. Also, a BBC Brazil investigation has revealed that an army of so-called social media cyborgs tried to influence the country’s presidential election. Why have so many women in so many different cultures and eras been denounced as witches? BBC Africa’s Sammy Awami visits a village in his home country of Tanzania where, just four months ago, five women were murdered after being accused of witchcraft. Sammy meets a witch doctor who believes he has met a witch and talks to a local politician who is trying to stop the killings. (image: Donald Trump enjoying his Diet Coke at a Foundation Dinner at the Waldorf Astoria, New York. Photo Credit: Brendan Smialowski/Getty Images)