A new study published in the American Journal of Preventive Medicine assesses what the impact over 20 years would be for a tax or advertising ban on sugar-sweetened drinks, compared with other strategies to reduce obesity in adolescents, such as increased exercise. In 2009-10, an estimated 1 in 3 American youths between the ages of 2 and 19 were overweight or obese, and 17 percent were obese. Studies have observed that obese adolescents tend to remain obese as adults, so developing strategies to tackle obesity during childhood is essential. Increasingly, states are adopting laws and regulatory tools to boost physical activity and healthy eating. However, federal policies are more effective at reaching larger populations. The researchers selected three out of a proposed 26 federal policies for evaluation. These were:
- After-school physical activity programs
- A 1¢ per ounce excise tax on sugar-sweetened beverages
- A ban on child-directed fast food television advertising.
For each of these policies, the researchers reviewed available literature published between 2000 and 2012. Microsimulation models — looking at a simulated school-aged population after 20 years of policy implementation — were then created to estimate the impact for each policy on diet, physical activity and body mass index (BMI).
All three policies would reduce prevalence of childhood obesity
Analyzing their results, the researchers found that, in the simulations, all three policies were effective at reducing the prevalence of childhood obesity.
The researchers found that the 1¢ tax would reduce obesity while also generating revenue that could be invested in new obesity prevention strategies.
The models also suggested that these strategies would be particularly effective at reducing childhood obesity in black and Hispanic populations, who have higher rates of obesity than other racial/ethnic groups. The simulations show that after-school activity programs would reduce obesity the most among children aged 6-12 (by 1.8 percent), the advertising ban would reduce obesity the least (by 0.9 percent), and the tax on sugary drinks would reduce obesity the most in adolescents aged 13-28 (by 2.4 percent). Lead investigator Alyson Kristensen, MPH, of Partnership for Prevention, Washington, DC, says that although the results show that all of the policies would reduce obesity, the 1¢ tax is the best option. She says that this tax reduces obesity while simultaneously generating significant revenue that could be invested in additional obesity prevention strategies. Kristensen adds:
“Unfortunately, implementation of any of these policies in the near term is extremely unlikely. However, this may change as the evidence base for these policies grows and changes in public knowledge increase calls for stronger governmental action. Research showing the harms of consuming SSBs continues to grow and the need for new revenue sources may spur Congress to consider a national SSB excise tax, such as the recently introduced SWEET Act.
In the meantime, the findings support state- and local-level action to enact SSB excise taxes, promote physical activity in after-school settings and reduce marketing and advertising of unhealthy foods and beverages in public schools.”
The link between soda and obesity
Rising consumption of sugary drinks has been identified as a major contributor to the childhood obesity epidemic. A typical 20-ounce soda contains 15 to 18 teaspoons of sugar and upwards of 240 calories. A 64-ounce fountain cola drink could have up to 700 calories. People who drink this “liquid candy” do not feel as full as if they had eaten the same calories from solid food and do not compensate by eating less. Beverage companies in the US spent roughly $3.2 billion marketing carbonated beverages in 2006, with nearly a half billion dollars of that marketing aimed directly at youth ages 2–17. And each year, youth see hundreds of television ads for sugar-containing drinks. In 2010, for example, preschoolers viewed an average of 213 ads for sugary drinks and energy drinks, while children and teens watched an average of 277 and 406 ads, respectively. Yet the beverage industry aggressively rebuffs suggestions that its products and marketing tactics play any role in the obesity epidemic. Adding to the confusion, beverage industry-funded studies are four to eight times more likely to show a finding favorable to industry than independently-funded studies. However, independent investigations have yielded consistent results regarding the harmful health effects of soda. Specifically, the evidence clearly shows that:
Sugary drink portion sizes have risen dramatically over the past 40 years, and children and adults are drinking more soft drinks than ever. 
- Before the 1950s, standard soft-drink bottles were 6.5 ounces. In the 1950s, soft-drink makers introduced larger sizes, including the 12-ounce can, which became widely available in 1960. By the early 1990s, 20-ounce plastic bottles became the norm. Today, contour-shaped plastic bottles are available in even larger sizes, such as the 1.25-liter (42-ounce) bottle introduced in 2011.
- Children and youth in the US averaged 224 calories per day from sugary beverages in 1999 to 2004—nearly 11% of their daily calorie intake. From 1989 to 2008, calories from sugary beverages increased by 60% in children ages 6 to 11 — from 130 to 209 calories per day — and the percentage of children consuming them rose from 79% to 91%.
- On any given day, half the people in the U.S. consume sugary drinks; 1 in 4 get at least 200 calories from such drinks; and 5% get at least 567 calories—equivalent to four cans of soda. Sugary drinks (soda, energy, sports drinks) are the top calorie source in teens’ diets (226 calories per day), beating out pizza (213 calories per day).
Sugary drinks increase the risk of obesity, diabetes, heart disease, and gout. 
- A 20-year study on 120,000 men and women found that people who increased their sugary drink consumption by one 12-ounce serving per day gained more weight over time—on average, an extra pound every 4 years—than people who did not change their intake. Other studies have found a significant link between sugary drink consumption and weight gain in children. One study found that for each additional 12-ounce soda children consumed each day, the odds of becoming obese increased by 60% during 1½ years of follow-up.
- People who consume sugary drinks regularly—1 to 2 cans a day or more—have a 26% greater risk of developing type 2 diabetes than people who rarely have such drinks. Risks are even greater in young adults and Asians.
- A study that followed 40,000 men for two decades found that those who averaged one can of a sugary beverage per day had a 20% higher risk of having a heart attack or dying from a heart attack than men who rarely consumed sugary drinks. A related study in women found a similar sugary beverage–heart disease link.
Cutting back on sugary drinks can help people control their weight. 
- People who regularly drink soda tend to consume more calories on a daily basis than those who don’t drink soda — this is particularly true for children. Studies in both children and adults have found that reducing sugary drink consumption can lead to better weight control among those who are initially overweight.
- Drinking water instead of soda has been shown to reduce overall calorie intake, therefore leading to weight loss. Studies show that replacing some or all sweetened beverages with water leads to significant weight loss in obese children and adolescents.
- Most impressively, research demonstrates drinking water instead of soda results in significant reductions in body weight and fat among overweight women, independent of diet and activity.
