Systems Thinking: The Diet Soda Puzzle

By Linda Fisher Thornton

Research is showing that diet sodas do not help prevent weight loss, and in fact may be a cause of weight gain. How can this be? Since the way we understand it depends on which kind of thinking we use, let’s examine the issue using several different kinds of thinking:

Cause-and-Effect Thinking

Using cause and effect thinking, we see that diet sodas have no calories, and conclude that therefore they could not cause weight gain. But that is not what research is showing. The human body has many systems that connect and they don’t necessarily respond in a cause-and-effect way.

Beginning to Use Systems Thinking

If we begin to use systems thinking, we may think about how the stomach processes the soda, and consider that something may happen when it’s being processed by the body. There are taste receptors in the stomach. The taste receptors in the mouth tell the ones in the stomach to expect something sweet and that triggers similar effects in the body to drinking a naturally sweetened soda. (Put Down the Diet Soda and Back Away, Julie Hanus, Utne Reader 5/6/2010)

Incorporating Multiple Connected Systems

Acknowledging that the body is made of many connected systems that work together reveals much more, and gets to possible causes, as this Inc. Magazine article explains:

“Regular sodas are full of calories, 140 per can and up. Diet sodas have zero calories. So it seems logical that replacing one with the other should help you lose weight, or at least stay the same weight. But no–several studies have proved conclusively that drinking diet soda is associated with weight gain.”

Minda Zetlin, Here’s the Science That Explains Why Drinking Diet Soda Makes You Gain Weight, Inc. Magazine

Another factor to consider is the systemic impact of the artificial sweetener that is used to sweeten diet sodas. And there are many more systemic effects to consider, including that diet soda appears to impair the function of the kidneys.

Now What?

This diet soda example is a good one to use to illustrate the importance of using systems thinking to understand complex problem that involve systems. Here is another recent article that speaks to the systemic effects.

A System of Systems

The human body is a complex connection of systems. The bottom line in understanding the diet soda puzzle is realizing that we can’t use cause-and-effect thinking to understand systems. It won’t give us an accurate indication of what’s happening.

There is also the issue that complex problems tend to have multiple causes, making them harder to unravel.

Systems thinking should be a skill we all develop, so that we can better understand the most complex issues we face. It should be taught early, and reinforced throughout our education system and in our workplaces. It’s not too late to start.