It is painful to be told that many of the foods we love contain a surprising amount of hidden sugar ("Exposing hidden sugar in food"; Tuesday).

But, shocking as the facts are, we need them to help us make informed choices on what we eat.

There needs to be widespread education on why the intake of excessive sugar - natural or added - can be so bad for our health.

Sugar is not just a benign empty calorie that will only make us gain weight if we eat too much.

Sugar is made up of glucose and fructose.

Fructose is digested primarily by the liver, and too much of it will lead to liver toxicity and other deadly chronic diseases, including hypertension and insulin resistance - the precursor to diabetes.

Because it is digested by the liver, fructose will not immediately lead to a rise in blood sugar level, so it seems like a healthier alternative, if you make food choices based on the glycaemic index.

How much sugar is too much? Well, the Health Promotion Board's guideline is about 10 teaspoons a day, and the World Health Organisation recommends six teaspoons a day.

Leung Hon Yew