A fundamental concept of weight management is energy balance ("Not always healthy to count calories" by Ms Audrey Chua Le Qing; yesterday).

When energy input (or calorific consumption) is more than energy output, one gains weight. The reverse is true for losing weight.

Eating fresh, unprocessed food alone will not help control our calorific intake.

For example, an adult who requires 2,500 calories a day would gain weight over time by eating 5,000 calories of cabbage, avocados and nuts every day.

That same adult would likely lose weight by consuming 1,000 calories of soft drinks and fruit yogurt every day.

Of course, there are other health perils of such a diet laden with sugar - diabetes, for example.

Ms Chua raises valid points about inaccurate calorie counts on nutrition labels and restaurant menus, and about calorific needs differing across individuals.

But these difficulties do not change reality.

We can try to overcome these difficulties - and indeed, there are many tools available these days that help determine our calorific needs and help track our calorific consumptions - or we can choose the easy way out and ignore them.

Either way, the fact remains that weight gain or loss depends on the fine science and art of attaining energy balance.

The Health Promotion Board has made good efforts in making calorie information more easily available to Singaporeans.

But more work needs to be done to educate the public about the importance of counting calories for the purpose of weight loss.

Angeline Wong Hui Wei (Ms)