Sugar-sweetened science: Coca-Cola, exercise and complexity

This week a New York Times article reported that the Coca-Cola company was funding a new non-profit organization called the Global Energy Balance Network dedicated to shifting the obesity discussion away from calorie intake and instead focusing on energy output. Their message: don’t worry so much about what you eat (and drink—like sugary Coca-Cola products). If you want to reach and maintain a healthy weight, work on exercise—that will help much more than cutting calories.

Here’s the message (via the article) from one of the organization’s members:

“Most of the focus in the popular media and in the scientific press is, ‘Oh they’re eating too much, eating too much, eating too much’ — blaming fast food, blaming sugary drinks and so on,” the group’s vice president, Steven N. Blair, an exercise scientist, says in a recent video, announcing the new organization. “And there’s really virtually no compelling evidence that that, in fact, is the cause.”

So is this true?

There are actually two complicated stories to explain the existence of this organization and its message. The first one is about what happens when industry partners very closely with scientific research, especially when that industry has a lot to gain (or lose), depending on the outcome of that research. Philosopher (and one of our readers!) Dan Hicks has worked on the politics and science of GMOs (genetically modified foods), and has found lots of ways that both scientific and political concerns about GMOs have been sidetracked or ignored. Here  is an interview he did about the issue, if you’re interested.

Public health policy and nutrition experts are criticizing the message, saying that it’s just a tactic on the part of Coca-Cola to engineer doubt about the contributors to obesity in order to continue selling its products. This is a well-known strategy, most famously used by the tobacco industry in its battle to deny that smoking was hazardous for your health. There’s a great book  (and even a film) on this issue.

There’s lots more to say about the first story, but I’m going to shift to the second one, which is about where the truth is with respect to this message. Just to remind us, here’s the message:

To maintain a healthy weight, get more exercise and worry less about cutting calories.

What do we know about exercise and body weight? First, science is complicated, and a process as complex as body weight regulation is governed by a lot of factors: genetics, calorie intake, physical activity, maybe to some extent type of food/beverage intake (the science on e.g. sugar and carb intake effects is still in progress), and lots of other things.

But we do know, through loads of studies (here  and here for instance) that physical activity has much less of an effect on body weight than calorie intake does.

There’s evidence here that diet plus exercise interventions have a greater effect on body weight reduction (in the short term) than diet interventions alone. However, we also know that in the long term (which for science and medicine means five years or more), no regiment of diet, exercise, diet plus exercise, or magic potions and incantations results in reliable maintenance of weight loss. Sam and Tracy and others have blogged about this a lot, like here and other places too.

So, as far as we can tell, it’s simply not true that exercise has more of an effect on body weight than calorie intake. In fact, there’s evidence that it has little effect at all on its own.

BUT: exercise does have all sorts of positive effects on our health and well-being.

There’s evidence here that physical activity can prevent, delay, and help slow the development of type 2 diabetes, even in the absence of significant weight loss. Basically, being active is good for what ails ya. You name it, physical activity helps it. Here’s a list from the Centers for Disease Control:

• Reduces the risk of dying prematurely.
• Reduces the risk of dying from heart disease.
• Reduces the risk of developing diabetes.
• Reduces the risk of developing high blood pressure.
• Helps reduce blood pressure in people who already have high blood pressure.
• Reduces the risk of developing colon cancer.
• Reduces feelings of depression and anxiety.
• Helps control weight.
• Helps build and maintain healthy bones, muscles, and joints.
• Helps older adults become stronger and better able to move about without falling.
• Promotes psychological well-being.

But, look—there, item 8: helps control weight. It’s on the CDC list! So maybe those Coca-Cola-funded scientists have a point after all.

Sigh. Okay, one more time: when you dig into the details, you’ll see that the CDC’s message is a complicated one about the role of exercise and weight loss and maintenance. It’s the same one the other medical studies are saying: exercise does burn calories, and exercise is great for your health, but it just turns out that (for a bunch of complicated reasons), exercise is not the key to weight loss.

The good news (which is emerging on a lot of fronts) is that maybe we don’t need a key to weight loss after all. It’s not a door we have to beat down and try to storm through in order to live happy and healthy and active and awesome lives. We need keys to better health, and luckily there are a lot of them around.

The role that sugar-sweetened beverages (like the approximately 470 out of 650 products Coca-Cola sells) plays in obesity is an ongoing area of research (which I won’t discuss here, but probably will sometime). But the point is that trying to address body weight through exercise is bad science and bad medicine.  And however sugary sweet it may be, it leaves a bad taste in my mouth.