Health Habits Work Better Together: Evidence from the Transtheoretical Model


Marie-Josée (MJ) Salvas Shaar, MAPP ’07, CPT, has studied, tested, coached, and taught smart health habits for over 13 years. Combining positive psychology with fitness and nutrition, she created a coaching method that builds better sleep, food, mood, and exercise habits, as described in her book, Smarts and Stamina: The Busy Person’s Guide to Optimal Health and Performance, which includes 50 practical health-building activities. Today MJ gives keynotes for corporate wellness programs and offers continuing education for wellness professionals, who can license her Smarts and Stamina Online program. Full bio. MJ’s articles are here.

The pieces must fit together...The pieces must fit together...

The pieces must fit together…

Would you consider sending your child to a school that covers the whole K-12 English curriculum in grades 1, 2 and 3, all of math in grades 4, 5 and 6, history in grade 7, geography in grade 8, biology in grade 9, and so on?

Of course not! Kids need to learn different skills at the same time because one reinforces the other. Strong language skills help a child understand math problems, and strong math skills help with science puzzles.

Similarly, your child’s maturity grows over time, and with that, his or her ability to understand complexity also grows. Shakespeare, Einstein, Newton, and Lincoln’s contributions are unlikely to be fully grasped by a 7 year old.

Academic ability is therefore like a puzzle where all the pieces fit together, and the challenge levels need to match the maturity levels of the students.

The same goes for our health skills. Maturity also plays a role here. We need to learn how to walk before we can run, we need to learn how to cook at home before we can definitively trash junk food, and we need to control momentary emotional impulses before we can successfully meditate through chaos. When we eat and sleep well, we have active minds which bolster our moods, and we have active bodies that give us the energy to enjoy exercise. Being active makes it easier to fall asleep. Health skills go together and grow together.

Simultaneous Growth Applies to Health Promotion

SaS Health Promotion ModelSaS Health Promotion Model


The fact that most wellness programs promote either food or exercise habits in isolation puzzles me. We intuitively know that when we sleep poorly, we are drawn to snacking and overeating. We also know that nothing gets rid of a crappy mood faster than a good sweat and that lower stress levels contribute to a better night’s sleep. So why are so many programs treating sleep, food, mood, and exercise as if they were separate topics?

Those who have been part of the Smarts and Stamina community know where I’m going with this: our sleep, food, mood, and exercise habits are mutually reinforcing, not only because of how they make us feel subjectively, but also because of the biochemical activity that each generates in the body. For more information on this, check out our health promotion model.

“The message feels fresh and new to me: each of these habits is interdependent on the rest, but that there are ways to exploit those interdependencies, so that you build successes on other successes rather than trying and failing. Of course, it makes so much sense that I’m surprised it felt so new.” ~ Lilly Bradford in a review of Smarts and Stamina

Transtheoretical Model Trend: Working on Multiple Health Behaviors at Once

James O. Prochaska wrote in 2008 that interventions that try to change multiple health behaviors either simultaneously or sequentially are likely to be the future of preventive medicine. He introduces the idea of co-variation, also called co-action.

“Co-variation occurs when taking effective action on one behavior increases the odds of taking effective action on a second behavior. This phenomenon is different from co-occurrence where groups of particular behaviors are more likely to have higher prevalence in particular populations… Co-variation reflects behaviors changing together rather than behaviors occurring together.” ~ J. O. Prochaska

Being physically activeBeing physically active

   Being physically active

A recent paper by Sara Johnson and colleagues investigated co-action in three different studies. They found substantial evidence that co-action occurs, at least in the context of interventions based on the transtheoretical model.

In one study, participants were randomized to either usual care or interventions targeting up to three behaviors: healthy eating, regular exercise, and managing emotions without eating. Participants in the intervention group then received tailored reports providing feedback on their stage of change for each behavior (Precontemplation, Contemplation, Preparation, or Action), self-efficacy, and a few related topics. Following the results for up to 24 months, the study found that participants were roughly twice as likely as the control group to take action on a second behavior. To quote James Prochaska again, “Co-variation represents one innovative approach in which effective change on one treated behavior increases the odds of effective action on a second targeted behavior.”

Why does co-action occur? Here are some of the hypothesized reasons mentioned by Johnson and colleagues.

    Fruits and vegetablesFruits and vegetables

    Eat your fruits and vegetables…

  • Increases in self-efficacy from changing one behavior spill over and help people change another behavior.
  • Knowledge and skills learned from making one change transfer to making the other change.
  • Making one behavior habitual might free up self-regulatory resources to work on another behavior.
  • Individualized interventions based on the transtheoretical model may be particularly well suited to support co-action.

More research is needed to explore what makes co-action occur. Is it specific to the transtheoretical model, or can it occur in other contexts and approaches?

How to Be Healthy

People ask me every day how they can become healthier. Here’s my answer.

Start with whatever is easiest for you instead of what’s most difficult. If you have a hard time with your food habits (you wouldn’t be the only one!), then food is your problem, not your solution. Work on sleep, mood, and/or exercise first, and food will become less of a challenge. You’ll get the ball rolling, feel in control and capable of change, and quickly build on initial victories. That’s much more energizing and sustainable than trying to fix your weakest area first.

For clear strategies on how to tackle each of sleep, food, mood, and exercise, check out our book. It offers 50 research-based avenues to better health.


Shortlist of Sources

Johnson, S., Paiva, A., Mauriello, L., Prochaska, J., Redding, C., Velicer, W. (2014). Coaction in multiple behavior change interventions: Consistency across multiple studies on weight management and obesity prevention. Health Psychology. 33 (5), 475–480. Abstract.

Prochaska, J. (2008). Multiple Health Behavior Research represents the future of preventive medicine. Preventive Medicine, 46(3), 281–285. Abstract.

Shaar, M.J. Britton, K. (2011). Smarts and Stamina: The Busy Person’s Guide to Optimal Health and Performance. Philadelphia, PA: Positive Psychology Press.

Image Credits
Still puzzled courtesy of Roberta Romagnoli / wererabbit
Being physically active courtesy of Nick-K (Nikos Koutoulas)
Fruits and vegetables courtesy of Hellebardius


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