Researchers tested a smartphone app designed to help people quit smoking, drink less, eat healthier, and exercise more. They studied over 5,400 people in Sweden who wanted to change their habits. The app had six different features, and the researchers tested each one separately to see which actually worked. They found that getting feedback about your current habits, setting specific goals, and staying motivated were the most helpful. When people combined feedback with motivation support, they ate even more fruits and vegetables. This study helps app makers understand which features are worth including.
The Quick Take
- What they studied: Which parts of a health-change app actually help people improve their eating, drinking, smoking, and exercise habits?
- Who participated: 5,419 adults from Sweden (age 18+) who searched online for help changing at least one unhealthy habit. They were a mix of people from the general public, not just one specific group.
- Key finding: Three app features worked best: getting honest feedback about your current habits, setting clear goals with a plan, and receiving motivation support. When feedback and motivation were combined, people ate more fruits and vegetables—about one extra serving per day.
- What it means for you: If you’re using an app to change your habits, look for one that shows you where you stand now, helps you set realistic goals, and keeps you motivated. These features appear to work better than other options. However, this is just one study, and results may vary for different people.
The Research Details
This was a carefully designed experiment called a factorial randomized trial. Think of it like testing different combinations of pizza toppings to see which ones people like best. The researchers randomly divided 5,419 people into different groups, and each group got a different combination of six app features: (1) feedback about current habits, (2) goal-setting and planning tools, (3) motivation messages, (4) skills and tips, (5) mindfulness exercises, and (6) text message reminders they could write themselves.
Everyone used the app for four months, and researchers measured their alcohol use, fruit and vegetable intake, physical activity, and smoking habits at two and four months. By testing different combinations, the researchers could figure out which features actually made a difference and whether some features worked better together than alone.
This approach is much smarter than just testing the whole app at once, because it shows exactly which pieces are helping and which aren’t.
Most health apps include many features, but nobody really knows which ones actually help. This study is important because it breaks down the app into individual pieces and tests each one. That way, app makers can focus on what actually works and remove features that don’t help. It also shows that some features work even better when combined, which helps create more powerful apps.
This study is well-designed with several strengths: it had a large number of participants (5,419), used proper randomization so groups were fairly matched, and was double-blind (meaning both participants and researchers didn’t know which features each person was getting until the end). The study was registered before it started, which is a good sign. However, most participants were from Sweden and likely had internet access, so results might be different in other countries or populations. Also, people who volunteer for health studies might be more motivated than average.
What the Results Show
The screening and feedback component was the clear winner. When people got honest feedback about their current habits, they ate more fruits and vegetables—about one-third of an extra serving per day at two months, and about one-quarter extra at four months. This might sound small, but it’s a real improvement. The feedback also helped reduce heavy drinking episodes (like binge drinking) by about 9% at four months.
Goal-setting and planning tools also helped people change their behaviors. When people set specific goals and made plans to reach them, they were more likely to stick with changes. Motivation support—like encouraging messages—also made a difference.
Interestingly, when researchers combined feedback with motivation support, the results got even better. People who got both of these features together ate significantly more fruits and vegetables than people who got just one or the other. This suggests that feedback works best when paired with encouragement.
Other features like mindfulness exercises, skills tips, and text message reminders didn’t show strong effects on their own, though they might still be helpful for some people.
The study looked at four main health behaviors: alcohol use, diet, physical activity, and smoking. While the feedback component showed the strongest effects on diet (eating more fruits and vegetables) and drinking habits, the results for physical activity and smoking were less clear. This might mean the app works better for some habits than others, or that people need different approaches for different behaviors. The study also found that different combinations of features worked better for different outcomes—there wasn’t one perfect combination for everything.
Previous research has shown that digital health apps can help people change habits, but most studies tested whole apps without knowing which parts actually worked. This study fills that gap by testing individual components. The finding that feedback and goal-setting are most effective matches what researchers have found in other studies about behavior change. However, this is one of the first large studies to test so many components together and look at how they interact, making it a valuable addition to the research.
Several limitations should be considered: First, most participants were from Sweden and had internet access, so results might not apply everywhere. Second, people who volunteer for health studies are often more motivated than average, which might make the app seem more effective than it would be for the general public. Third, the study only lasted four months, so we don’t know if changes stick around longer. Fourth, the study relied on people reporting their own behaviors, which might not always be accurate. Finally, some effects were modest in size, meaning while they’re real, they might not feel huge to individual users.
The Bottom Line
If you’re looking for an app to help change your habits, choose one that includes: (1) honest feedback about where you stand now, (2) tools to set specific goals and make plans, and (3) regular motivation and encouragement. These three features have the strongest evidence. Combining feedback with motivation appears especially powerful. Confidence level: Moderate—this is solid research with a large sample, but results may vary by person and situation.
This research is relevant for anyone wanting to improve their eating, drinking, smoking, or exercise habits. It’s especially useful for people who prefer digital tools and apps over in-person coaching. However, if you have serious addictions or health conditions, you should talk to a doctor or counselor rather than relying only on an app. The findings may be less applicable to people without regular internet access or those who prefer non-digital support.
Based on this study, you might notice changes in eating habits within two months, with continued improvement at four months. Changes in drinking patterns took a bit longer to show up (four months). For smoking and exercise, the timeline is less clear from this study. Remember that behavior change is gradual—don’t expect overnight transformation. Most people need consistent use of the app over several months to see meaningful results.
Want to Apply This Research?
- Track daily fruit and vegetable servings using a simple photo log or counter. This is the behavior that showed the clearest improvement in the study. Aim to add one extra serving per day and log it each evening.
- Set one specific, measurable goal (like ’eat 5 servings of fruits and vegetables daily’) and create a concrete plan (like ‘add vegetables to lunch and snacks’). Use the app’s feedback feature to check your progress weekly, and read the motivation messages regularly—don’t skip them, as they appear to boost results.
- Check your progress every two weeks using the app’s feedback feature. If you’re not seeing changes after four weeks, adjust your goal or plan. Continue tracking for at least four months to give the app time to work. Consider pairing the app with one accountability partner (friend, family member, or online community) for extra motivation.
This research describes what worked in a scientific study, but individual results vary. This study is not a substitute for professional medical advice, diagnosis, or treatment. If you have serious health concerns, addiction issues, or are taking medications, consult with a healthcare provider before making major lifestyle changes. Apps can be helpful tools, but they work best as part of a complete approach that may include professional support. Results shown in research may not apply equally to everyone.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.