Beat the post-lunch slump

To counter the mid-afternoon energy slump, the first thing most of us do is grab a bar of chocolate and a cup of tea. Now Cadbury's has launched a Boost chocolate bar packed with the natural stimulant guarana to pick you up. But do the products designed to combat a lack of energy really work? We asked a busy financial consultant to roadtest five drinks and bars that claim to boost energy levels.

Every afternoon, Dominic Rice, 23, from Finchley, suffers a drop in his energy levels. He gets up at 6am and works an 11-hour day. For him, the worst point in the day is at about 5pm. "I lose my concentration, I might be on the computer and find myself staring into space and feeling generally tired. It's pretty hectic in my job and the adrenaline from the day's work keeps me going, but five is a quiet time of the day. Sometimes I pop out for a quick walk to get some fresh air - but soon it will be too cold and wet to get out every afternoon."

We asked him to try a different product every afternoon for a week and to record how he felt.

Go-Co, £1

Describes itself as milk chocolate with an energy high. It was aimed at clubbers and launched this year in Ibiza. More than three or four bars at one time is not recommended. Not for children, pregnant women or people with high sensitivity to caffeine.

Active ingredient: Guarana, a well-proven stimulant that contains naturally-occurring caffeine. Should only be used occasionally.

Dominic says: "I do eat chocolate regularly and I was disappointed with the taste of Go-Co. It was not too bad, but it wasn't very enjoyable. The flavour of the guarana definitely overwhelms the chocolate flavour.

Half an hour after eating it, I felt full of energy. But it soon became too much, my hands were shaking and I felt jittery.

The effect was too crude - I was awake, but I found it hard to remain focused on my work. In a club it would have been perfect - I would have been able to jump around all night on it, but in an office I need mental stimulation. I would not take this again."

Energy score: 6/10

Red Bull, £1.09

An energy drink that claims to stimulate metabolism, increase physical endurance, improve concentration and reaction speed. Not suitable for diabetics, children and those sensitive to caffeine.

Active ingredients: Taurine and caffeine. Taurine is a nonessential amino acid from ox bile. It supposedly helps fight fatigue by interfering with the brain's production of the sleep-inducing chemical serotonin. But like taking too much caffeine, it can raise the heart rate, putting susceptible people at risk.

Dominic says: "Out of all of them this was the best, and I found that, as long as it is drunk ice cold, it tastes fine. I tried it at room temperature once and it was disgusting. It smells horrid and tastes revolting. After I drank it, I felt I had more energy and my concentration increased. I didn't feel shaky and it wasn't an overload. It definitely did more for me mentally and it worked very quickly - within 20 minutes I felt a rush and it lasted about two hours." Energy score: 9/10