Overweight and obese children tend to drink more sugar-sweetened soft drinks than normal weight children.
And taxing such drinks, in combination with other public health measures, could help contribute to the fight against the child obesity epidemic.
However, a study of soft drink consumption patterns of more than 1,000 schoolchildren in Cork, suggested it was unlikely the introduction of a 'sugar' tax would have direct short-term impacts on obesity levels.
But the authors of the study, led by Dr Janas Harrington of University College Cork, said more likely a tax would "have more indirect impacts such as reduction in consumption of these beverages; increased consumption on non-sugar beverages such as water; product re-formulation by manufacturers and changes in public attitudes and discourse."
The government plans to introduce a tax next year on sugar-sweetened drinks (SSD).
Data from 1,075 schoolchildren aged 8-11 years was obtained for the Cork Children’s Lifestyle Study which was conducted in primary schools.
The researchers found 18% of children with plausible energy intake were overweight (16%) or obese (2%) compared with 25% of the total sample.
Of those with plausible energy intake, 82% were SSD consumers. Mean calories from SSDs increased incrementally between weight categories: SSD contributed 108 kcal for normal weight children and 155kcal for overweight/obese children, equating to 5.8% and 7.6% respectively of total daily calories.
The next steps in the research will be to monitor consumption of such drinks in the run-up to the introduction of the tax and to assess the impact of the tax following its introduction.
The obesity epidemic remains a public health crisis with the potential to reverse recent favourable trends in life expectancy and undermine the financial viability of health systems.
Though the epidemic has many causes, links between the consumption of sugar-sweetened drinks and excessive weight gain in children were observed.
Furthermore, excessive consumption is associated with increased prevalence of dental caries.
The authors, in this new study, aimed to provide evidence of the magnitude of the consumption of SSDs in Ireland and to explore the association between SSD consumption and overweight and obesity.
Dr Harrington said: "While no single measure will reverse current trends in obesity, given the high level of consumption of SSD and the lack of nutritional value of these products, action needs to be taken to reduce consumption, particularly in high consumer groups, including children.
"There is a compelling case for the introduction of public policy to reduce SSD consumption in the population. The introduction of a tax on SSDs in combination with other public health interventions has the potential to have a measurable effect on the scale of the epidemic of childhood obesity."