In 1980, a woman promised her dying sister to change how Americans thought about breast cancer. Thirty years later, the result – the Susan G. Komen for the Cure Foundation – is one of the nation’s largest non-profits, and one of the most successful triumphs in public health marketing and changing health habits.

Now, Komen is in the midst of a public relations crisis, brought on – as you probably know – by a small, boneheaded move: the Komen foundation said it would stop giving a small amount of money to Planned Parenthood. One Komen board member said the decision was to appease social conservatives.

Why is the backlash to this decision so intense, however? Why has it almost killed a 30-year old organization?

Because when the Komen Foundation decided to start targeting women’s health habits, it entered into a special relationship with its supporters. When marketers influence habits, they influence peoples’ self-identity. And so when a group or company does something that doesn’t correspond to our core values, it feels like a betrayal.

That’s why liberal college students are fine with eating Domino’s Pizza, even though the company’s founder is a major donor to anti-abortion and anti-gay rights organizations. Domino’s isn’t part of anyone’s self-identity.

But the Komen foundation has helped millions of women develop new habits: breast self-examination, regular mammograms, exercising for better health. And habits (unlike, say, pizza) are at the core of how we view ourselves.

To see how this works, consider a series of experiments from earlier this decade by researchers creating new habits.

In one 2006 study, two Australian researchers — Megan Oaten and Ken Cheng — enrolled two dozen people between the ages of eighteen and fifty in a physical exercise program and helped them create weight-lifting and aerobics habits. Before the experiment began, most of the subjects were self-professed couch potatoes. Now they were in better physical shape. But they were also healthier in other parts of their lives, as well. The more time they spent at the gym, the fewer cigarettes they smoked and the less alcohol, caffeine, and junk food they consumed. They were spending more hours on homework and fewer watching TV. They were less depressed.

Oaten and Cheng designed another experiment. This time, they signed up twenty-nine people for a four-month money management program. They set savings goals.  Unsurprisingly, people’s finances improved as they progressed through the program. More surprising, they also smoked fewer cigarettes and drank less alcohol and caffeine — on average, two fewer cups of coffee, two fewer beers, and, among smokers, fifteen fewer cigarettes each day. They ate less junk food and were more productive at work and school. It was like the exercise study: As people developed habits in one part of their lives — in the gym, or a money management program — it strength spilled over into what they ate or how hard they worked.

Why? Because habits are created by changing our sense of self. The cues and rewards that create habits are integrally linked to our values and how we view ourselves.

Which is a huge strength for public health (or other kinds of) marketers. If you can create a habit, you are making your product part of a consumer’s self-identity. When someone habitually takes a vitamin you sell, you have made your product part of their system for re-affirming a commitment to health. When someone uses Nike shoes to habitually jog, Nike becomes part of how a customer habitually feels good. Our habits are ourselves – and as Oaten and Cheng proved, that sense of self expands into all kinds of other parts of life, as well.

And that’s why, when the Komen Foundation, or a vitamin seller, or Nike acts badly, customers take it so hard. Imagine that the vitamin company suddenly revealed it also manufactured cigarettes. Or newspaper stories showed that Nike’s shoes were made by children working in unhealthy conditions. It would feel like a betrayal because the very product that gave us our sense of self now turns out to be a false promise. Our natural instinct is to turn our back on the betraying product. Which is why the backlash against the Susan G. Komen Foundation has been so intense: it’s easier to turn your back on a betrayer than to have to re-evaluate all the spillover habits the organization has helped create.

So what does this mean for marketers today? If your company or organization is trying to change peoples’ habits, what lesson should you take away from the Komen fiasco?

The lesson is that if you use habits as tools, you must be prepared to study every decision very carefully. If you are selling habits, you are selling an identity, and so you must be careful not to betray the values your customers adopt alongside your product.

Lululemon, for instance, doesn’t just sell yoga pants, it sells lifestyle habits, and thus a self-identity. As a result, when the founder decides to celebrate a controversial philosopher who believes the poor deserve to be poor, there is backlash. The Gap, on the other hand, can sell the same pants, and no one cares about the company’s politics.

In the case of Komen, pulling funding from Planned Parenthood looks like pandering, it looks like fear, it looks like hypocrisy. And a freedom from the fear of breast cancer, from the hypocrisy of gender double standards, is why the organization exists in the first place. When Komen backtracks, it feels like betrayal, because the group has become part of so many peoples’ habits.

Some of the ideas and portions of this post draw on my book, The Power of Habit