OBLIVIOUS ADDICTS: Josiah Lester used to drink the equivalent of seven flat whites a day.

The Kiwi obsession with coffee and energy drinks is terrifying a nutritionist who says we don't yet know the full impact over-consumption of these products has on our health.

A stroll down Victoria St, and through the nooks and crannies of the central city, will tell you many things about the culture of Hamilton.

We love a good jeweller, a beautiful florist, a mega chain carrying electronics and of course there are the bars.

But one place that pops up every few shops is a cafe.

Coffee has become ingrained in our society as a necessity - it is what we consume to get the morning kick.

But are we consuming too much?

And are we aware of the components of our daily flat white?

AUT Professor of Nutrition Dr Elaine Rush has been studying the effects of caffeine on the human body and she is terrified of what may be happening to the health of New Zealanders.

The truth is, no-one is quite sure of the effects, she reveals, but this is not a green flag to say that caffeine is safe. It just means they don't know.

Every body reacts differently to caffeine, Dr Rush explains. It is dependent on genes, body type, ethnicity, age, gender, the list goes on.

"It is almost random, which means it's very hard to tell what will happen to each person."

But one thing she is sure of is that caffeine has no place in our diet.

"Caffeine is a drug. It's not a nutrient and it's not a normal part of our diet. It doesn't provide any nourishment," she said.

And the scariest thing is that Kiwi kids are also getting a caffeine fix through energy drinks.

Consumption has skyrocketed, with sales volumes in New Zealand and Australia rising from 34.5 million litres in 2001 to 155.6 million litres in 2010.

According to most sources the average amount of caffeine in a double shot of espresso is 77 milligrams as compared with the average 80mg in a 250ml can of energy drink.

But Rocket Coffee roaster Glen Woodcock said Kiwi coffee could contain more than this because we drink it strong.

British baristas would generally use 7 grams of coffee to produce the morning fix; New Zealand baristas were more likely to use up to 18g, he said.

He estimated that caffeine made up 1 per cent of the bean, so with an 18g coffee there is about 180mg of caffeine in a flat white.

But it depended on your barista.

"Theoretically, the more you extract from the bean, or the longer you let the shot run, the more caffeine you'll get," he said.

Rocket Coffee barista Malcolm Hutt said energy drinks were more of a problem than coffee.

"I think a natural product like coffee is likely to be less harmful than manufactured caffeine that's in energy drinks.

"Coffee is not dangerous," he said. "You would have to drink a fair amount of coffee for it to be harmful."

It is something he knows from experience - too many coffees once put him in the back of an ambulance.

He was judging a coffee competition and once he hit the 30 coffee mark, things started to go downhill.

"I tasted 36 coffees and I just had a kind of seizure," he said.

Mr Hutt said that just like a bartender regulates their customers' alcohol intake, he would do the same if he felt someone was in danger, but it was not a situation that has arisen in his 15 years of making coffee.

"If someone sat here and had too many in a row, I'd probably tell them: You need to go and burn off some of that caffeine you've just put into your body."

LIKE A LONG HANGOVER

Josiah Lester had no idea he might have been an addict.

He's a pretty normal guy - mid-twenties, managing a retail store and he has couple of beers at the weekend but there's no way he's an alcoholic.

But it was the silent drug that had him hooked. Caffeine.

Mr Lester was drinking the equivalent of at least seven flat whites a day before he went cold turkey two weeks ago. His day would begin with a couple of quadruple-shot long macchiatos, followed by two or three triple-shot mochas throughout the day. On the weekend there would also be a Powerade and a Red Bull or two chucked in for good measure.

It didn't occur to him that he might have had an addiction to the stuff before he made the break, due to a serious case of stretching himself thin. The caffeine was making him anxious and he'd just come down with another bout of the flu.

But the lack of caffeine hit him harder than he thought. He was lethargic, and his flu symptoms were exaggerated. It was, as he put it, "horrible".

"I'd liken it to a hangover but it only started to subside after day three or four," he said.

Giving it up has gone well so far - he had a minor slip-up with a green tea but only because he was unaware it contained caffeine.

It made him feel "like a million bucks" but it wasn't enough to get him back on the caffeine.

He does miss it a bit, though.

"I still never get that alertness that I had."