'Soda Politics' & Science: 5 Issues

Highlights: 
  • We need to put all research and education in context and evaluate its quality objectively.
  • Substituting diet soda for regular soda does help with weight loss.
  • Caramel food coloring has not been found to be carcinogenic. 
  • Unfortunately, demonizing a single food or ingredient like soda is not going to help us combat obesity or chronic health conditions.
  • Soda is just one part of a bigger energy balance equation.

This week, with the release of Soda Politics, the Food Insight team consulted our e-readers. ‘Soda’ is one of those words that can be very divisive among dietitians, like those on the Food Insight team, and nutrition enthusiasts, like myself. In the interest of setting the stage, let’s start with what’s not up for debate. Soda doesn’t come with nutritional benefits. It’s not a necessary part of your nutrition. If it’s consumed in too great a quantity, it can throw off your calorie balance. Nobody is arguing that soda should flow down from the mountain top.

But is it mysteriously ‘worse’ than other moderately consumed treats? Are its ingredients safe? Is eliminating all soda the magic solution to all of our diet and health problems? Making these kinds of promises or generating fear isn’t actually going to get us to our health goals.

Marion Nestle says on page 2 that an occasional soda “is hardly a health concern.” But the following 400 pages seem to argue otherwise. From raising doubts about ingredient safety on limited evidence to implications that soda is the great evil in the fight against obesity and chronic health conditions, the book misses or misinterprets important research findings. Here’s our take on 5 issues that Nestle discusses, and where the science stands.

We need to put all research and education in context and evaluate its quality objectively.

analyze-the-evidenceAs Food Insight/FACTSFollowers fans know, we receive funding from both public and private sources (including a number of companies, some of whom are discussed in the book), and we regularly dive into studies funded by both public and private interests with a range of views. How do we put this variety of interests in context, whether it’s reading an outside study or making internal decisions?

We look at the interests in play, particularly the level of transparency (something we pride ourselves on) they engage in. Then, we scrutinize the methods. We look deeply at study design, the totality of evidence, and the qualifications of communicators and researchers who are involved. We have designed tools (like this one and this one) for ourselves and others that give users the power to analyze the quality of research themselves.

We’d encourage everyone to hold research to a high standard, no matter who funds it, and evaluate the totality of the science. It can be tough, time-consuming, and inconvenient, but this high standard is what we really need to talk about nutrition and food safety.

Bottom-line: There are a lot of biases that go into research. Methodologies are designed to control for biases in design, data collection, and analysis, so learn how to evaluate methodologies.

Substituting low-calorie drinks like diet soda for regular soda does help with weight loss.

low-calorie-beverage-infographic-linkLow-calorie sweeteners come up a lot in Soda Politics in the context of diet soda. No matter what kind of low-calorie sweetener we’re talking about, these ingredients contain few or no calories, and their safety has been confirmed by decades of research and FDA review.

Nestle asserts that it is “thoroughly evident that diet beverages do not help people control weight.” This claim is completely inconsistent with the body of research on low-calorie sweeteners- just look at the most comprehensive scientific evaluation of low-calorie sweeteners and body weight and composition studies to date. Miller and Perez conducted a recent meta-analysis of 15 randomized-control trials (the research gold standard) and nine prospective cohort studies on low-calorie sweeteners and weight management, spanning 35 years. The finding? Substituting low-calorie sweetened beverages for their regular-calorie counterparts contributes to weight loss (American Journal of Clinical Nutrition, June 2014).

A recent study published by Peters et al in Obesity in June further contributes to the existing evidence that low-calorie sweeteners, like those used in many diet sodas, can aid in weight loss. In fact, the study found that compared with those who drank water, people who drank beverages sweetened with low-calorie sweeteners lost more weight, felt less hungry, and benefitted from reductions in total and LDL cholesterol levels.

Soda Politics’ claims that low-calorie sweeteners might be linked to an increased insulin response are extremely shaky, since they draw from a pretty flawed study in mice. The vast majority of research shows that these sweeteners do not affect insulin or glucose levels, which is extra important for those with diabetes.

Bottom-line: Low-calorie sweeteners like the ones in diet soda are an extremely useful option for people with diabetes or reducing their calorie intake. 

No, caramel food coloring has not been found to be carcinogenic.

caramel-coloring-not-carcinogenicNestle refers to 4-MEI, a component of caramel coloring as a “potential carcinogen,” which makes consumption sound like a pretty major health risk. Where is that coming from?

4-MEI was classified as a “carcinogen” under California's Prop 65, resulting from a single (pretty darn questionable) study. In this single study, researchers fed mice 4-MEI in an amount equivalent to drinking thousands of cans of soda every day for their entire lifetimes, finding an increase in likelihood of lung cancer. These results have not been reproduced in rat studies or in humans, and they don’t remotely reflect how we consume 4-MEI.

Furthermore, extensive research suggests that 4-MEI from caramel coloring does not pose a safety threat to humans at current levels of consumption. In fact, the FDA has confirmed that there’s “no reason to believe that there is any immediate or short-term danger presented by 4-MEI at the levels expected in food from the use of caramel coloring.”

Bottom-line: Extensive research and FDA has confirmed that caramel coloring is safe, and using one poor study to suggest otherwise is deceptive.

Unfortunately, demonizing a single food or ingredient like soda is not going to help us combat obesity or chronic health conditions.

scale-obesity-problemThere are a lot of claims like this in play throughout the book. Do liquid calories contribute to weight gain more than calories from solid foods? Is consumption of soda causing diabetes, obesity, or hypertension?

To her credit, Nestle owns the fact that the reliance on (largely self-reported) intake data for research on sugar-sweetened beverage is problematic, saying she “did the best [she] could with all of this, but you cannot take the numbers presented here too literally. They are best considered approximations.”

The reliance on studies that report ‘associations’ regarding soda consumption is a major problem for drawing meaningful conclusions. It’s the 9th-grade adage about correlation versus causation in action. Like a recent study on sugar-sweetened beverages, association studies can make for flashy headlines. What they can’t do is establish causation.

What causes diabetes? It’s not a simple answer. Diabetes is a disease characterized by high blood sugar that results from the body's inability to properly use or make insulin.  While family history and genetics play large roles in the development of type 2 diabetes, other factors, such as low activity level, poor diet, and excess body weight, can also increase your risk for type 2 diabetes.

Consuming too many calories from ANY single source, including soda, can lead to weight gain and is a risk factor. An actionable step to improve your health is identifying what your major sources of excess calories are and then working to cut back on those items. Keep splurges sensible; focus on getting the nutrients you need from fruits and vegetables, whole grains, dairy, and lean protein; and make sure you’re balancing your intake with physical activity.

The battle against obesity and chronic health conditions is complex and can be discouraging. We understand the temptation to oversimplify and try to find a single scapegoat for an issue that’s so intimidating. But ultimately, singling out one food or beverage doesn’t help any of us eat more healthfully, and it doesn’t help broader public health goals.

Soda is just one part of a bigger energy balance equation.

chalk-scale-energy-balanceNestle believes that moderation of soda intake is difficult to achieve, saying that “moderation is not a term that applies to many soda drinkers.” This is a pretty aggressive generalization that tends to ignore our ability to exercise self-control (yes, I’m a soda drinker too, and yes, I take this generalization somewhat personally). Other than a few references to the supposed lack of moderation possible in soda consumption, there’s little discussion of calorie intake or energy balance.

Scientists and government agencies agree that “energy balance” is key. It's not a talking point- it's what the science says.  According to the 2010 Dietary Guidelines for Americans, “Overweight and obesity will result from excess calorie intake and/or inadequate physical activity.”

When it comes to weight management or weight loss, it’s the total calories that matter most. Our bodies need a certain amount of calories to complete day-to-day activities and exercise. Each person has unique calorie needs that depend on a number of factors, including height, weight, age, gender, and activity level.

When we consume too many calories, the excess calories are stored as body fat. This can contribute to weight gain and, ultimately, health issues. Talking about obesity, or chronic health issues, and ignoring energy balance is completely counterproductive.

Bottom-line: No single food makes a bad diet, or is responsible for obesity or health conditions. Maintaining your energy balance and eating a diet of balance, variety, and moderation is the best way to live healthfully.

Big Picture

We all want to be healthier, and to live in communities that are healthier, too. There’s room in our diets for ‘sensible splurges,’ and, whether the splurge is a piece of cake, game-day snacks, or a soda, it’s important to consume moderately, combine with a variety of nutritious options, and balance your food with physical activity. It takes real effort and commitment to do this in our own lives and support each other in living healthfully. Despite the obvious appeal for headlines, stoking unfounded fear about ingredients and beating up on a particular food aren’t going to get us there.

This blog post was written with contributions from Liz Sanders, RD, MPH; Megan Meyer, PhD; and Kris Sollid, RD.

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