Philadelphia recently introduced a 1.5-cent per fluid ounce levy against sweetened beverages as part of the fight against obesity and its related diseases and disorders. The tax covers sodas, energy drinks, and juice drinks (less than 50% juice).1 For example, this tax adds an extra $2.16 to a 12-pack of 12-oz cola cans. Sugar “sin taxes” incentivize customers to reduce or eliminate their consumption of sugary soft drinks. This initiative is similar to the taxes on alcohol and tobacco across the United States.
Mexico’s sugar tax (10% surcharge) reduced sugar sweetened beverage sales by 6% overall and most among poor households. The Mexican National Institute of Public Health predicted soda consumption to drop by 22 liters per year, from 163 liters, preventing 630,000 cases of diabetes by 2030. The Mexican soda tax was intended to pay for drinking water infrastructure at schools (thereby reducing soda consumption indirectly).2
Philadelphia’s tax impacts the poor much more than middle-class and well-to-do consumers as a percentage of household income. The poor spend a greater fraction of their income on groceries, on average, and a flat tax has a greater impact on those with smaller budgets. The Philadelphia “sugar tax” benefits the city’s universal preschools, libraries, parks and recreation centers, social services, and municipal pensions. “Sugar tax” opponents assert the tax is paternalistic and worsens our country’s hunger crisis. Philadelphia’s “sugar tax” applies to artificially sweetened beverages unlike many, if not all, other similar taxes. The broader tax favors wholesome products such as 100% juice products and unsweetened water. A tax on sugar only, like Berkeley California’s tax, favors the proliferation of artificially sweetened products. Children and adults consumed 200% and 54% more non-sugar sweetened beverages in 2012 compared to 1999.3
The health impacts of these sweeteners are controversial and unclear. The American Diabetes Association recommends artificial sweeteners in moderation to reduce total calorie and carbohydrate consumption. However, the organization desires more research on this topic.3
A team of researchers found insufficient evidence that artificial sweeteners reduce consumer sugar consumption in a study published on January 3, 2017 by PLoS One.4
Sugar sweetened beverages contain 46% of the average American’s dietary added sugar and rarely contain appreciable levels of micronutrients, protein, or essential fatty acids. The World Health Organization recommends people limit calories from added sugar to less than 10% of total calories.
The sweetness of artificial sweeteners may increase consumers’ appetites by spurring the release of certain gut hormones (eg, ghrelin) and posing a moral hazard. Consumers may consume more, or less healthy, food if drinking a non-sugar sweetened beverage. Past research has found high artificial sweetener consumption is associated with higher body mass index. However, the connection could be either that heavier people seek out non-sugar sweeteners or these products induce weight gain. The favored hypothesis tends to follow the financial interests of study sponsors. Generally sugar companies show artificial sweeteners are unhealthful and artificial sweetener manufacturers suggest their products promote weight loss. The study authors could not conclude non-sugar sweeteners have any impact on weight and the evidence was weakest among children.
Acidic beverages, such as colas and other carbonated beverages, damage teeth independent of their sugar content. Tooth decay, especially among children, is lifelong damage impacting quality of life (eg, pain) and maintaining a healthful diet (eg, uncooked vegetables and apples).
Non-sugar sweeteners include artificial aspartame, saccharin, and sucralose, as well as the herbal supplement stevia. Patients should carefully examine non-sugar sweetened products to determine their contents. Phenylketonuria patients should avoid aspartame because of its phenylalanine content. Bafflingly, Trader Joe’s “Stevia Extract” is 97% sugar by weight. The unexpected lactose has calories, causes tooth decay, and causes digestive discomfort in patients with lactose intolerance.5 Coca-Cola’s Truvia contains erythritol (a low calorie sugar alcohol), stevia extract, and “natural flavors.” Erythritol is zero-calorie and does not contribute to tooth decay.6
The Philadelphia “sugar tax” smartly covers both sugary and artificially sweetened beverages because both varieties have negative health impacts without providing essential nutrients. Future research on the role of non-sugar sweeteners needs to minimize conflicts of interest and confounding variables.