Supersize vs Superskinny - Almost enough to put you off your tea

I've made you a mountain of curry for tea," announced my flatmate last night just as I sat down to watch Supersize vs Superskinny.

"Brilliant," I replied as she handed me the plate piled high with Thai green vegetables.

We don't normally eat our tea in front of the TV – honest – but last night events had transpired against me and setting the table seemed completely unachievable.

But five minutes into the programme, I was beginning to wonder if eating my dinner was going to be completely unachievable.

Starting off with a visit to America where "supersizing" has got an upgrade, host Dr Christian (an apparently real life doctor whose features have been based on an Action Man doll) introduces us to a jumbulance – yes that's a jumbo-size ambulance for, err, jumbo-size patients – and we meet a woman whose weight is forcing water to gather in pockets all over her limbs.

It's actually pretty eye-opening stuff but I was really hungry so I admit that while I paused temporarily, I didn't actually stop chipping away at my curry mountain.

Back in the UK and Dr Christian brings patients Rob and Hayley into his slightly disturbingly named Feeding Clinic to confront their weight issues.

Both are aged 25 and are 5ft 3in – but the similarities stop there.

Youth worker Rob weighs in at a staggering 35st 10lb and puts away an impressive 7,000 calories a day while mortgage advisor Hayley is just 6st 12lb and survives on less than 850 calories – that's probably about half the calorie content of my by now fast-depleting curry mountain.

Both have deeply-rooted emotional issues with food. Rob comfort eats – up to 832 cream donuts a year apparently – while Hayley views eating as an inconvenience.

She survives on copious amounts of sugary tea, Peperami sticks and the odd piece of cheese. Both diets are dangerous and both patients know it but it takes two days in the Feeding Clinic eating each other's meals to really make them see it.

During the diet swap Hayley is forced to eat cakes, chips, fried breakfasts and at one stage – horror of horrors – a mountain of Thai green curry. I nearly put my spoon down altogether. But then I realised that her curry was made with chicken and full-fat coconut milk while mine was a vegetarian alternative with half-fat milk. It was a close one, but I carried on regardless.

After a few days, they leave the clinic with a tailor-made diet plan. Six weeks later, they return to let Dr Christian know how they're getting on.

Hayley has gained 6lb while Rob has lost 1 stone 10lb. It's all progress but with a BMI of 86 rather than a healthy 25, Rob still has a long and gruelling diet journey ahead of him.

It's enough to put you off your tea – well, almost.

Amy Burns