THERE is nothing to brighten up the day like a sweet treat.

Whether your poison is parma violets or you have a taste for chocolate – we all have to indulge our sweet tooth every now and again.

But what if that sweet treat really is poison?

It used to be that you couldn’t say the word ‘fat’ without people believing they’d put on five pounds from the mere mention of it.

But sugar has become the modern nemesis.

The average Brit consumes around 238 teaspoons of sugar a week without realising.

So what happened when residents of the aptly named Sweethill Lane on Portland, went without the white stuff?

Well first of all, they had to wake up to their sugar habits. One, a fan of Turkish Delight chocolate thins, finds out that per 100g they contain 51.5g of sugar.

And think your morning cereals are a healthy choice? So did Sweethill Lane resident Sue... until she discovered they contain 35g of sugar per 100g.

Presenter John Cuthill said: “All the emphasis has been on fat, we’re being told ‘cut back on fat, cut back on fat’.

“But the amount of sugar we are consuming is going up.

“A lot of people don’t realise how much they are consuming.

“Government experts are saying we need to halve our sugar intake.

“It’s leading to problems such as obesity and other health issues and is costing the NHS.”

He said there is ‘confusion’ about the amount of sugar in foods – you might think a low fat yogurt is a better choice but the fat is replaced with sugar.

Scientists say if sugar is not converted quickly to energy, it is stored as fat via a process called lipogenesis.

Groups like Action on Sugar say the mistake that people make is thinking that a calorie of energy from sugar is the same as a calorie of energy from fat.

And eating sugary foods also causes a ‘spike’ in blood sugar.

For the show, John underwent a brain scan to see the effects of eating sugary foods.

He said: “When my brain realised what was coming, it was firing up.

“Our brains are hard-wired to seek out energy for our bodies.

“But the levels of sugar that we have on a daily basis are a lot higher than when we were living in caves.”

So whose responsibility is it to monitor the amount of sugar we’re putting in to our mouths?

After filming the show, John says the answer is ‘complicated’.

He says that some coffee chain drinks that are of the fruit variety can contain the same amount of sugar as 20 doughnuts.

“Yet you wouldn’t sit down and eat 20 doughnuts in a row,” John said. But he added that we ‘can’t just point the blame’ at manufacturers – consumers have a responsibility too, as does the government to ensure people are educated.

BBC Inside Out South sugar special will be aired tonight.