Tax on saturated fat–does it work?

Taxation of the fat content of foods for reducing their consumption and preventing obesity or other adverse health outcomes

BACKGROUND

Overweight and obesity are increasing worldwide and are considered to be a major public health issue of the 21st century. Introducing taxation of the fat content in foods is considered a potentially powerful policy tool to reduce consumption of foods high in fat or saturated fat, or both.

OBJECTIVES

To assess the effects of taxation of the fat content in food on consumption of total fat and saturated fat, energy intake, overweight, obesity, and other adverse health outcomes in the general population.

SEARCH METHODS

We searched CENTRAL, Cochrane Database of Systematic Reviews, MEDLINE, Embase, and 15 other databases and trial registers on 12 September 2019. We handsearched the reference lists of all records of included studies, searched websites of international organizations and institutions (14 October 2019), and contacted review advisory group members to identify planned, ongoing, or unpublished studies (26 February 2020).

SELECTION CRITERIA

In line with Cochrane Effective Practice and Organisation of Care Group (EPOC) criteria, we included the following study types: randomized controlled trials (RCTs), cluster-randomized controlled trials (cRCTs), non-randomized controlled trials (nRCTs), controlled before-after (CBA) studies, and interrupted time series studies. We included studies that evaluated the effects of taxes on the fat content in foods. Such a tax could be expressed as sales, excise, or special value added tax (VAT) on the final product or an intermediary product. Eligible interventions were taxation at any level, with no restriction on the duration or the implementation level (i.e. local, regional, national, or multinational). Eligible study populations were children (zero to 17 years) and adults (18 years or older) from any country and setting. We excluded studies that focused on specific subgroups only (e.g. people receiving pharmaceutical intervention; people undergoing a surgical intervention; ill people who are overweight or obese as a side effect, such as those with thyroiditis and depression; and people with chronic illness). Primary outcomes were total fat consumption, consumption of saturated fat, energy intake through fat, energy intake through saturated fat, total energy intake, and incidence/prevalence of overweight or obesity. We did not exclude studies based on country, setting, comparison, or population.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for all phases of the review. Risk of bias of the included studies was assessed using the criteria of Cochrane's 'Risk of bias' tool and the EPOC Group's guidance. Results of the review are summarized narratively and the certainty of the evidence was assessed using the GRADE approach. These steps were done by two review authors, independently.

MAIN RESULTS

We identified 23,281 records from searching electronic databases and 1173 records from other sources, leading to a total of 24,454 records. Two studies met the criteria for inclusion in the review. Both included studies investigated the effect the Danish tax on saturated fat contained in selected food items between 2011 and 2012. Both studies used an interrupted time series design. Neither included study had a parallel control group from another geographic area. The included studies investigated an unbalanced panel of approximately 2000 households in Denmark and the sales data from a specific Danish supermarket chain (1293 stores). Therefore, the included studies did not address individual participants, and no restriction regarding age, sex, and socioeconomic characteristics were defined. We judged the overall risk of bias of the two included studies as unclear. For the outcome total consumption of fat, a reduction of 41.8 grams per week per person in a household (P < 0.001) was estimated. For the consumption of saturated fat, one study reported a reduction of 4.2% from minced beef sales, a reduction of 5.8% from cream sales, and an increase of 0.5% to sour cream sales (no measures of statistical precision were reported for these estimates). These estimates are based on a restricted number of food types and derived from sales data; they do not measure individual intake. Moreover, these estimates do not account for other relevant sources of fat intake (e.g. packaged or processed food) or other food outlets (e.g. restaurants or cafeterias); hence, we judged the evidence on the effect of taxation on total fat consumption or saturated fat consumption to be very uncertain. We did not identify evidence on the effect of the intervention on energy intake or the incidence or prevalence of overweight or obesity.

AUTHORS' CONCLUSIONS

Given the very low quality of the evidence currently available, we are unable to reliably establish whether a tax on total fat or saturated fat is effective or ineffective in reducing consumption of total fat or saturated fat. There is currently no evidence on the effect of a tax on total fat or saturated fat on total energy intake or energy intake through saturated fat or total fat, or preventing the incidence or reducing the prevalence of overweight or obesity.

Anticipatory effects of the implementation of the Chilean Law of Food Labeling and Advertising on food and beverage product reformulation

This study evaluated the anticipated food and beverage product reformulation by industry before the Chilean Law of Food Labeling and Advertising (Law 20.606) was implemented in June 2016 requiring a front-of-package (FOP) warning label for products high in sodium, total sugars, saturated fats, and/or total energy. Fieldworkers photographed a purposive sample of packaged food and beverage products in February 2015 (n = 5421) and February 2016 (n = 5479) from six different supermarkets in Santiago, Chile. The same products collected in both years (n = 2086) from 17 food and beverage categories with added critical nutrients (nutrients of concern: sodium, total sugars, and saturated fats) were included in this longitudinal study. The average change in energy and critical nutrient content was estimated by category. The number of warning labels potentially avoided because of reformulation was determined. Between February 2015 and February 2016, no category experienced reductions >5% average change in energy or critical nutrient content; and some increased in critical nutrient content. Few products (<2%) would have avoided at least one warning label with reformulation. In a diverse sample of food and beverage products, there was minimal reformulation by industry in anticipation of the implementation of the 2016 Chilean Law of Food Labeling and Advertising.