In an effort to combat widespread obesity, British officials are weighing plans to expand an existing tax on sugary drinks to include packaged milkshakes and lower the sugar content levels at which the surcharge is triggered.

The sugar tax currently starts on drinks with 5 grams of sugar per liter. That will drop to 4.5 grams of sugar per liter under a budget proposal set to be unveiled on Wednesday.

The added “milkshake tax” would apply the levy to other pre-packaged sugary drinks such as flavored milks, milkshakes, sweetened yogurt drinks, chocolate milk drinks, and ready-to-drink coffees. It would not apply to “open drinks” prepared in cafes and restaurants.Many of those products have as much added sugar as sodas

Many of those products have as much added sugar as sodas and the government has positioned the tax as a way to fight obesity. The United Kingdom has the third highest rate of adult obesity in Europe, which is blamed for driving up diabetes, heart disease, and cancer levels.

Dairy UK, which promotes dairy products, says it was “disappointed” in the decision.

“Our products play an essential role in providing valuable nutrition — with milk and yogurt-based drinks a convenient, affordable and tasty way for many, especially children, to meet their recommended intakes for a range of nutrients,” the chief executive of Dairy UK, Dr. Judith Bryans, said in a statement.

The British Soft Drinks Association said while the new threshold would create an additional cost burden for the industry, it was relieved a plan to lower the threshold to 4 grams per liter was abandoned.

It says the industry has been making steady progress in cutting sugar in drink consumption. “Since 2015, sugar consumption from soft drinks is down 43%, and today just 6% of take-home sugar in diets in Great Britain comes from soft drinks,” the association said in a news release.

The Obesity Health Alliance said evidence has shown the current tax has been linked to reductions in tooth extractions in children and cases of obesity in girls 10-11 without harming industry growth.

“Ending the exemption for sugary milkshakes and bringing more sugary soft drinks into the levy is a sensible and long-overdue step to protect children’s health — especially their teeth,” the executive director of the alliance, Katharine Jenner, said in a statement.

The government reported hospital admissions for children requiring tooth extractions are down more than 28 percent among children under the age of five.

The organization claims the calorie intake by children could drop further among children when the new taxes go into effect and bring about dramatic health and economic benefits.

The new rules need to be approved by the Parliament and would not go into effect until January 2028 to give companies time to remove sugar from beverages to avoid the new tax.

The United States has had its own battle against sugary drinks. Health Secretary Robert F. Kennedy Jr. has signed waivers to several states allowing them to ban the purchase of sugary drinks and candy under the SNAP program.

New York has considered an excise tax on sugary drinks for years at the state level — including in the last session — but there hasn’t been enough support to pass the legislature.

Governor David Paterson attempted to include a sugar tax in his budget in 2009 and again in 2010 but lawmakers stripped it from the final budget.

Mayor Michael Bloomberg attempted to limit the portion sizes of sugary drinks sold at restaurants in New York City in 2012 but that rule was overturned after a court battle.