Question to the Department of Health and Social Care:

To ask His Majesty's Government on the basis of what evidence they have estimated that the extension of the soft drinks industry levy, announced on 25 November, could prevent almost 14,000 cases of adult obesity and nearly 1,000 cases of childhood obesity.

The changes to the Soft Drinks Industry Levy announced in the 2025 Autumn Budget are:

• reducing the lower sugar threshold to 4.5 grams per 100 millilitres, as it is currently at five grams per 100 millilitres; and
• removing previous exemptions for milk-based and milk substitute drinks.

These changes will apply from 1 January 2028. They are designed to encourage producers to reformulate their products to reduce sugar levels and avoid paying the levy, thus reducing calories consumed from the drinks in scope.

Evidence shows that energy dense diets such as those that are high in sugar can contribute to excess calorie intake, which if sustained leads to weight gain and obesity. Population-level policies therefore aim to create a healthier food environment to reduce excess calories and obesity prevalence across the entire population.

The Department carried out a health benefit assessment to estimate the calorie reduction from these changes through reformulation and substitution to alternative drinks. Together, these changes reduce sugar and calorie intake from drinks across all age groups.

The analysis used nutrition data from the National Diet and Nutrition Survey, sales data from Worldpanel by Numerator, formerly Kantar WorldPanel, and a series of assumptions to estimate the sugar and calories removed from diets due to the changes. The approach, data sources, and assumptions are set out in detail in the published assessment.

This analysis estimates per person per day calorie reductions of 0.3 kcal in five to 10 year olds, 0.4 kcal in 11 to 18 year olds, 0.3 kcal in 19 to 64 year olds, and 0.2 kcal in those aged 65 years old and over.

The BMI Prevalence Model was then used to simulate the change in obesity prevalence from the estimated change in calorie intake at a population level. This model is based on weight loss equations by Henry (2005), a sample of height and weight data from Health Survey for England, and population data from Office for National Statistics.

This modelling estimates that a calorie reduction of this scale could translate into reducing cases of adult obesity by almost 14,000 and childhood obesity by almost 1,000.