A Stanford scientist shares a simple way to stick with good habits even when you're feeling lazy

With the New Year comes new expectations: that you'll be productive and energized and motivated all the time. Go you!

This is kind of silly. Realistically, there will be times - a lot of times - when you're lazy and unmotivated to do anything.

The key is to anticipate that laziness and prepare for it.

That's according to BJ Fogg, a psychologist and director of the Persuasive Technology Lab at Stanford.

If you want to make healthy behaviors easier, Fogg says, it's not about trying to increase your motivation so much as taking advantage of motivation when you do have it.

In a 2013 interview with Ramit Sethi, author of "I Will Teach You to Be Rich," Fogg explained how to ride what he calls the "motivation wave," or the fluctuations in our motivation levels.

"Motivation only has one role in our lives and that's to help us to do hard things," Fogg said. So when your motivation is high, you want to do all those hard things that make future healthy behaviors easier. If you want to exercise more, that would mean signing up and paying for a trainer and scheduling appointments.

In a 2012 presentation, Fogg explained how the motivation wave might apply to a behavior like healthful eating. One strategy is to do is something hard that reduces barriers to the desired behavior.

So when you come home from the grocery store and your motivation is high, you should wash your vegetables, chop them up, and put them in clear containers in your refrigerator where you can see them.

"Later, throughout the week as your motivation sags, your goal of eating more vegetables is easier to do," Fogg said in the presentation.

Another strategy: When your motivation is high, you can do something that increases your capability to achieve the goal. So maybe you can try your hand at a new (nutritious) recipe that'll be a lot easier the next time you use it.

Once you hear it, the idea sounds ridiculously simple. It's a matter of accepting that your motivation will occasionally plummet, and that that's okay. If you can predict the obstacles you'll face during those times, you can help your future lazy self to be healthier and more successful.

The interview with Sethi and Fogg is featured in Sethi's Ultimate Guide to Habits and the full interview is available to premium users on Ramit's Brain Trust. You can watch part of the interview here: