Yerba mate: special brew

A weight-loss tea that's full of antioxidants but gives you a caffeine buzz? Catherine Townsend gives up coffee to find out if yerba mate really is the top tip

I've always shied away from making New Year's resolutions, but 2005 was the year that my morning coffee habit got seriously out of control. When I realised that I could barely crack one eye open without a latte, I knew it was time to make a change.

So I was intrigued when I heard about yerba mate, the South American herb that supposedly produces a coffee-like buzz when brewed into a tea - but does not result in headaches or jittery side effects. Like green tea, the drink is loaded with antioxidants, making it ideal for the January detox season.

But the most likely reason that Madonna and Hillary Clinton reportedly can't drink it fast enough is because of the tea's reputation as an appetite suppressant. Matt Dillon, Meg Ryan and Gwyneth Paltrow also drink yerba mate-based tonics, while Moby sells it in his New York café, Teany. So I decide to give the brew a road test.

Yerba mate is popular in South America, especially in Argentina, where cowboys first started brewing it in the early 1800s. Today, it's typically served in a gourd and sipped through a metal straw. The legend of the beverage's health benefits has grown over the years, and these days drinkers claim that mate can detoxify blood, boost immunity, protect from cold, reduce stress and suppress appetite.

Katie Healey, a spokesperson for Cotswold Tea, which sells both tea bags and loose mate on its website, www.cotswoldtea.com, says that she has noticed a surge in demand for the tea in the past few months.

"It is one of our most popular products, and we have loads of customers who order 20 boxes at a time. I drink four cups a day myself, and find that it makes me feel really mentally alert, and fills me up so that I'll have another cup instead of grabbing a chocolate cake. A lot of people say that it has helped them with weight loss. I can say that for me personally, the health benefits are incredible."

On day one I sample some "traditional" mate in bags. It looks and smells like stale oregano. It doesn't taste much better: I'm reminded of flavoured hay, but I add a bit of lemon and manage to choke it down. It's definitely not Starbucks, but I do notice that an hour later I don't have the usual headache that I would have suffered had I stuck with caffeine-free herbal tea. This is probably because, according to the box, yerba mate contains about 20mg of caffeine per serving, as opposed to about 137mg for the average cup of coffee. It's enough to stave off the withdrawal symptoms that I'm having.

On day two, I try adding milk and sugar to the brew, which does make it taste a little better - though I have to pour in so much sweetener that it probably defeats the purpose of ingesting an appetite suppressant.

Over the next few days, I decide to branch out into a custom "matecino" blend of tea with almond bits, cocoa and cornflower blossoms that I bought from the trendy New York teahouse Sympathy For The Kettle's website. It smells lovely, and is definitely less bitter - but I can't help noticing that it reminds me of weak coffee. I decide to go back to basics, which isn't easy, because despite fans' claims that the beverage "grows on you", the bottom line is that it tastes pretty gross.

But several companies have started offering chai, vanilla and various other flavoured formulas, so perhaps I'll just have to keep experimenting. Healey suggests that I shop around. "I hated the taste at first, but wanted to stick with it to find out what everyone was raving about. Now I love it, especially the chai one."

Despite the off-putting taste, I'm not ready to give up on the strange brew because, over the holiday, I notice that although my entire family is ill with flu and bronchitis, I manage to escape unscathed.

In fact, I feel fantastic. For the first time in recent memory, I'm sleeping soundly - because unlike coffee, yerba mate doesn't seem to disrupt my sleep cycle, and doesn't irritate my stomach. I'm also noticing an energy boost, and it doesn't make me feel as dehydrated as coffee or tea. Unfortunately, I haven't lost any weight yet. Then again, that could be down to my gorging on Christmas puddings!

So for now, I'm going to stick with yerba mate. But I can't promise to quit coffee "cold turkey". Tea may be the healthier option, but soy lattes are still invading my dreams.