Instead, it passes straight through our gut without providing us with any calories but helps to sweep out toxins and waste.

There are two types of fibre in foods:

1 Insoluble fibre gives a coarse texture to foods. It's found in wholegrains and cereals, bran, potatoes, and the skins of fruits and vegetables. This type of fibre doesn't dissolve in water.

2 Soluble fibre gives food a gel-like consistency. It's found in fruits, vegetables, oats, barley, beans, legumes, pulses, and pectin. This type of fibre dissolves in water.

High-fibre foods stop you from snacking. They fill you up for longer, so you are less likely to snack on fatty and sugary foods between meals.

Fibre helps to maintain a healthy gut. As insoluble fibre can absorb or hold on to water, it helps keep the contents of your gut soft and moist, and so helps to prevent constipation.

Fibre reduces the likelihood of developing colon cancer. Insoluble fibres hold on to substances that can cause cancer. Slow-moving waste allows more time for cancer-causing compounds to come into contact with the walls of the intestines.

By eating more fibre, you shorten the time it takes for food waste to pass through the intestines.

Soluble fibre can help lower blood cholesterol by trapping fatty substances in the intestines so the body can't absorb them.

Fibre also helps people with diabetes control their sugar levels in the blood by slowing down the digestion of carbohydrates.

So how much fibre do we need?

Most heath organisations suggest that adults should eat between 20-35grams of fibre a day. But most Asians eat much less than this.

A dietary survey conducted in Singapore in 1983 showed that most adults eat only 15 grams a day. Hong Kong people eat even less - a 1995 study showed that intake was less than 10 grams a day.

A 2005 survey conducted among kindergarten children in Hong Kong found that 30 per cent of the 561 children interviewed were constipated.

For children over two years of age and teens, the American Dietetic Association uses this formula to determine how much fibre is needed:

(Age in years + 5) grams.

For example, a 13-year-old needs (13+5=) 18 grams of fibre a day.

Dheeya's Diary

Breakfast: Milk or tea, Royal Jelly, vitamin C, multivitamin and Evening Primrose supplements. Doesn't usually eat anything - sometimes take an apple, orange or cookies to school

Lunch: School canteen: salmon sandwich, salmon Caesar salad or vegetable bean wrap; lemon tea

Dinner: Hainan chicken rice, rice and curry or Singaporean fried bee hoon; water

Snacks: Fruits; hot chocolate, coffee, tea, water or lemon tea