Red Wine

Who’d be a twin? As a baby you get half the attention you deserve, as a teen you worry if your twin is better-looking and when you grow up, the BBC starts experimenting on you.

Or at least they will when they have polished off their existing Gemini guinea pigs, Doctors Chris and Xand van Tulleken. Last time out, Horizon (BBC2, 9pm, 20 May) made them eat sugar and fat for a month. By the end of the episode Dr Chris was left on the brink of diabetes.

Undeterred, he’s back for another go, along with his brother. Both have signed an insurance-heavy dotted line before putting their bodies through the wringer and under the microscope. And this time around they were drinking booze in order to determine the effect binge drinking has on the body, compared with a moderate, but steady, intake.

So Xand drank 21 units over seven days, about a glass of wine every night, while Chris racked up the shots on a Saturday. As the show subsequently proved - and you won’t have guessed it - necking 21 vodkas in fours hours is not always a good idea. It ruined Chris, who insisted he was fine after shot 21, staggered to the taxi, started weeping and woke up full of regret.

Predictably, neither twin emerged with a liver in tip-top condition, but let’s hope they recover, because as unhinged as the nascent human experimentation reality genre is, it’s fascinating stuff. And using the twins brings the inevitable ‘everything in moderation’ message to life in an informative, entertaining and absorbing way.