Sugar vs Fat, TV review: Binge twins make a meal of it

Fat chance: Xand van Tulleken in ‘Horizon: Sugar vs Fat’ (BBC)

Last night's Horizon (BBC2) pitted the two best food types against each other in "Sugar vs Fat", a battle which – as I flounce towards a chubby middle age – I'm calling as a score draw. They're both brilliant.

Alas, thanks to a backlash in the fructose-bloated US, sugar is 2013's diet bête noire. I spent a fun lunchtime this week with my colleagues dissecting the sugar content of my Appletiser (31 per cent of your daily allowance, FYI), but in the UK it's fat that has traditionally been the nutritional bogeyman. But which is worse?

Well there's only one way to find out – employ a pair of high-achieving scientist twins to binge on both for a month and find out whose innards take the bigger shoeing.

And so it was. Identical hunky docs Chris and Xand van Tulleken were our guinea pigs. Xand went on a high-fat, low-sugar diet; Chris did the opposite. Cue shots of lots of lovely pastries.

You may remember Chris and Xand from The Secret Life of Twins and Channel 4's Medicine Men Go Wild. Their schtick here was that their identicalness makes them perfect as a point of comparison for this food-based face-off. At the start of the film, the pair looked like the kind of blokes who would smash a full set of lights in the first round of Take Me Out; by the end, well, they appeared much the same but – like Morgan Spurlock after a month of Big Macs – felt a bit grubby.

Chris's carb-heavy blowout meant he could eat more calories but still feel hungry, whereas Xand's high-protein diet made him feel fuller because, we learned, fat and sugar have different effects on ghrelin, the hunger hormone. Fat, then, suppresses hunger, to a point. So get the bacon out. Or at least the eggs and the rest of the polyunsaturated/monosaturated mob. However, a gram of fat has twice as many calories as sugar and our bodies turn them into body fat more easily. So is that one-all?

The experiments continued with a bike race up Box Hill in Surrey with Team Sky's Nigel Mitchell fuelled by a tab of butter and an energy bar. Sugar won, easily.

The results of some of their tests were a bit odd. In fact, Chris's no-sugar diet almost led him to diabetes as it made his body less resistant to insulin. My punt before I watched the show was that it might conclude: don't have too much of each. And, quelle surprise, the twins' summing-up: "We know our enemy and it's the delicious combination of fat and sugar."