The juice bar cult has made fruit and vegetables attractive and fun. I spot young people sipping orange and carrot; peach, guava and pineapple; apple and celery; watermelon, mint and beetroot all perceived as healthy fare on-the-go.

Juice is also a big part of the detox concept, where it's supposed to "cleanse the digestive system" and "draw out toxins" although none of these claims can actually be proven.

The one big drawback is that juice is fruit that's been "concentrated". Juice packs in a lot of kilojoules/calories. It's fruit in a form that's all too easy to over consume. Once you remove the fibre and intact structure, your remove nature's brake to over consumption.

Let's compare apples with apple juice. A medium 200g apple provides 3g fibre and 300 kilojoules (70 calories) and takes a relaxing 5 minutes to eat.

In contrast, a 600ml apple juice (2 cups) provides zero fibre and 1300 kilojoules (310 calories). You can gulp it down in a mere 2 minutes.

This large juice, typical of the size sold by juice bars, is equivalent in food value to four apples but takes a fraction of the time to drink. It's a trap for health-conscious people. However it packs in nutrition for an underweight person with a small appetite or someone recovering from chemotherapy who can't eat much.

So, think of a large juice as a substantial snack rather than just something to quench your thirst. Order the smallest size you can or share one with a friend. Dilute juice with water or sparkling mineral water. Or order vegetable with it (like carrot with orange) to "dilute" down the sugars from the fruit.

*Catherine Saxelby is a nutritionist and author of Nutrition for Life. Get more healthy eating tips at her site at www.foodwatch.com.au