I disagree with the arguments put forth by Mr Chan Yeow Chuan ("Sugar tax may not be best weapon in war on diabetes"; last Friday). Singapore should consider a tax on sugar-sweetened beverages.

The war on diabetes has already started and we would be fighting a losing battle if we adopt a wait-and-see approach.

As a diabetes dietitian, I see the disease manifesting in many forms, from heart attacks to amputation and kidney failure. I am constantly encouraging people with diabetes to adopt a healthy diet and maintain a suitable weight.

For those who are overweight, all too often, when they manage to lose weight, it is due to a bout of illness, coupled with poor appetite.

Hence, I have found that even after educating patients, they do not make informed decisions. It is perhaps only with taxation that we can hope to alter behaviour.

All consumption taxes, including those on tobacco and alcohol, are regressive, representing a higher proportion of a low-income family's expendable income than that of the rich.

A tax on sugar-sweetened beverages is no different. But it is the poor who are much more likely to have unhealthy diets and experience ill health than the affluent. This leads to higher costs in the form of medication, more sick days off work and, ultimately, lower productivity.

Improving public awareness works only for the upper class, who are better able to make informed decisions. The economically underprivileged families tend to make decisions based on price.

I think most would agree with me that there is no place nutritionally for sugar-sweetened beverages.

But when we walk into the supermarket and notice a 1.5-litre bottle of soft drink selling for between $1 and $2 - in some cases, cheaper than water - we have to ask ourselves, what are we promoting?

The science about the link between sugar and diabetes may not be all that clear. But the decision to impose a tax on sugar-sweetened beverages should not be a scientific one but, rather, one of moral obligation.

Gerard Wong Choon Hoe