I have a protocol.

A way of eating and behaving that produces weight loss.

I learned it in Overeaters Anonymous. It’s tried and true.

When I explained it to my dear friend, she gaped at me in stunned silence.

“No, I can’t do that.”

“But let me ask you a question, do you drink Diet Coke,” she asked?

The answer is no. Not on the protocol.

The protocol is hard.

Giving up soda, “just for today,” is easier.

Giving up soda reduces weight, belly fat and inflammation, improves kidney function and bone strength, restores taste sensitivity, increases consumption of plain clear water and can solve just about every problem known to man.

Perhaps most important, however, is that giving up diet soda can act as a lever.

I can focus on and master one change.

This makes me more mindful. It give me a sense of mastery which then motivates me to do more.

Making one meaningful, small change, produces evidence that I am able to change.

I’ve proven to myself that I can abstain from Diet Coke.

One of my favorite books is “Go Wild.” Authors John Ratey and David Perlmutter tell the story of Beverly Tatum, president of Spelman College, whom they meet at California’s Rancho La Puerta.

Ms. Tatum was wrung out, gaining weight, sleep-deprived and . . . surprise . . . rather stressed.

So she set a hard-and-fast rule that she would abandon work at 10pm and sleep.

Improving her sleep hygiene allowed her to focus on nutrition and exercise, not only for herself, but also for the two thousand Spelman women, for whom she implemented a new wellness campaign.

Pulling one lever can motivate us to make more positive changes — in our own lives and those of others.

I can think “I’ve tried everything, I’ll always been this way, I’ll never be thin.”

It’s paralyzing.

Or I can think “I cut out Diet Coke. I’m capable of changing. What can I do next?”

It’s empowering.

Massive change requires massive action.

But massive action can start with small change. It builds from there.

Ms. Tatum’s small change was getting more sleep.

My friend’s is giving up Diet Coke.

What’s your lever?