Some governments tax sugary drinks and snacks in order to improve public health. I agree that this is an effective measure, although it works best when combined with other policies.
The main reason is price. When a product becomes more expensive, people usually buy less of it, and studies of the sugar tax introduced in the United Kingdom and in Mexico suggest that sales of heavily sweetened drinks fell noticeably. Companies also respond, because they want to avoid paying the tax. Many British soft-drink manufacturers reduced the sugar content of their products rather than raise prices, and this changed what millions of people consumed without requiring them to alter their behaviour. In addition, the revenue can be used for public benefit, for example to fund healthcare or school sports and meals.
Critics claim that consumers simply pay more and carry on buying the same items, particularly when the habit is strong. It is also said that the tax is unfair to poorer families, who spend a higher proportion of their income on food and therefore bear the greatest burden. These objections have some force. However, low-income groups also suffer the most from diet-related illnesses, so they gain most from healthier consumption, and the tax revenue can be directed back to them through free fruit in schools or lower-cost healthy food.
I also accept that education is vital. A tax alone does not explain why too much sugar is harmful, so public campaigns and clear labelling should accompany it to help people to change their habits permanently.
In conclusion, taxing sugary products is an effective way of reducing consumption and encouraging healthier recipes, and with fair use of the revenue and support from education, it can improve public health.