In January 2017, Philadelphia became the second city in the United States to implement a tax on the distribution of sugary and artificially sweetened beverages. Two years later, the tax is believed to have taken 83 million cans of soda off the streets — the equivalent of 28 million kgs of sugar (62 million pounds).

The world is facing an unprecedented health crisis: obesity. Worldwide obesity has nearly tripled since 1975, with more than 1.9 billion adults being overweight, and over 650 million being obese. Most of the world’s population live in countries where overweight and obesity kills more people than underweight, and although obesity is preventable through healthy nutrition and lifestyle, it shows no sign of slowing down.

Sugar is one of the main culprits in the current obesity crisis. There’s sugar in everything, from foods and sauces to sugary drinks, and the world just can’t seem to have enough of it. We’re eating too much sugar and it’s high time to stop this unless we want to deal with absolutely catastrophic consequences.

Sugary drinks are around 5-15% sugar, and contain essentially no nutrients. In other words, when you’re having this type of drink, you’re ingesting water and sugar, with no benefits. There is a mountain of science connecting sugary drink consumption to long-term health issues such as obesity and diabetes.

Health scientists and economists have long advocated for a sugary drink tax and, in 2017, Philadelphia took action.

“Taxing sugar-sweetened beverages is one of the most effective policy strategies to reduce the purchase of these unhealthy drinks. It is a public health no-brainer and a policy win-win,” said first author Christina A. Roberto, PhD, an assistant professor of Medical Ethics & Health Policy in the Perelman School of Medicine at the University of Pennsylvania. “It’s likely to improve the long-term health of Philadelphians, while generating revenue for education programs in the city of Philadelphia.”

The city implemented a 1.5-cents-per-ounce tax (50 cents per liter). The rationale behind the tax was twofold: on one hand, the tax would raise money which would be used for educational and health projects and, on the other hand, the consumption of sugary drinks would drop.

It worked.

According to Penn Medicine researchers, the consumption of sugary and artificially sweetened beverages dropped by 38% in chain food retailers, one year after the tax was introduced. This was projected to happen, but now there is official confirmation. Overall, between January 2016 and December 2017, there was a 59% reduction in taxed beverage sales at supermarkets, a 40% reduction at mass merchandisers, and a 13%reduction at pharmacies. This wasn’t caused by any external factor —  when researchers looked at sales just outside of Pennsylvania (where the tax was not applied), they found that sales actually increased. In a separate study, researchers also report that unemployment was not affected by the beverage tax, something which the sugary drinks industry claimed would happen.

“Philadelphia’s tax on sweetened drinks led to a huge reduction in sales of these unhealthy drinks one year after it was implemented and generated revenue for thousands of pre-k slots. That’s great news for the well-being of the people of Philly,” Roberto said.

Philadelphia isn’t alone in this endeavor. Several cities in the US (including San Francisco and Boulder) have implemented similar taxes, with similar positive results. However, at the national level, there is still no talk of such a tax in the US. Meanwhile, countries such as Mexico and the UK have implemented a sugar tax and have also reported reduced consumption after the tax.

Although there are some concerns regarding such a tax and there may be significant geographical variations, the overwhelming scientific consensus seems to be that taxing sugary drinks has a positive impact.

Results were published this week in JAMA,