Sugary drinks should be hit with a 20% tax, according to British doctors this week. This, they argue, would help ease the burden of obese people on the National Health Service (NHS), where poor diet costs the organization an estimated $9.35 billion (£6 billion) a year, greater than alcohol or smoking.    

In a new report, titled "Food For Thought" by the British Medical Association (BMA), doctors propose that the government should add a tax on high-sugar drinks, which has been shown to reduce their consumption in Mexico. The report also suggests that the money raised from the new tax should then be used to subsidize healthy foods such as fresh fruit and vegetables.      

“In the UK, the traditional public health challenges of undernutrition and unsafe food and water have been largely replaced by the risks of poor diet,” said Professor Sheila Hollins, current chair of the BMA Board of Science, in the report. “This type of diet [high in fat, sugar, and salt] underlies many of the chronic diseases that cause substantial suffering, ill health and premature death.”

The BMA estimate that 70,000 people a year die prematurely due to poor diet in the U.K. alone, accounting for around 12% of all deaths. This is only predicted to get worse: “We're looking at 30% of the UK population being obese by the year 2030, a large extent of that is due to the amount of sugar we're actually consuming without realising,” Dr. Shree Datta from the BMA told the BBC.

The BMA argue that increasing the tax on soda would cut the number of obese individuals in the country by around 180,000 people. The report comes ahead of the U.K.’s official Scientific Advisory Committee on Nutrition, which will publish its final advice on Friday, suggesting people should be halving the amount of sugar they currently consume.

Last year, Mexico made waves by taking the bold stance to levy a tax on sugary drinks, a move closely watched by the U.S. and other western countries, where obesity numbers are steadily rising. The country whacked the drinks with a 10% tax, lower than what was wanted by campaigners, and yet it still saw sales of soda drop by an average of 6% over the year, in line with what models predicted. The impact is similar to what was observed when tobacco was taxed, and the sales are expected to dip further over time.

The U.K. government say that they have no plan to introduce the tax, though the new report feeds into a growing voice in the west for one to be imposed. For example, Berkley, California saw a group of campaigners including health advocates, educators and local politicians win a case against “Big Soda” last year, succeeding where many other American cities have failed and passing a tax of one cent for every ounce of soda.

The report proposes that in addition to the soda tax, there should more limitations on the advertising of unhealthy foods to children, and mandatory standards on food across all schools, including improved teaching about cooking and healthy eating.