Researchers looked at 62 different studies about diet and inflammatory bowel disease (IBD) to understand why people quit these studies early. They found that most people (84%) actually finish these studies, which is pretty good. However, certain things make people more likely to drop out, like having to collect stool samples or studies that last 4-8 weeks. The research shows that the most complicated parts of studies—especially collecting samples—are what make people want to quit. This information can help doctors design better studies in the future that keep more people involved.
The Quick Take
- What they studied: Why do people stop participating in diet studies for inflammatory bowel disease, and what study features make people more likely to quit?
- Who participated: 3,523 people with inflammatory bowel disease across 62 different research studies that tested different diets or food supplements
- Key finding: About 84 out of every 100 people finish these diet studies, but people are much less likely to finish (only 75 out of 100) when the study requires them to collect stool samples
- What it means for you: If you’re thinking about joining a diet study for gut disease, know that most people do complete them. However, studies that require stool collection or last 4-8 weeks might be harder to stick with, so consider this when deciding whether to participate.
The Research Details
Researchers searched three large medical databases for all published studies about diet and inflammatory bowel disease between now and May 2024. They only included studies where people were randomly assigned to different diet groups (the gold standard for research). They looked at 62 studies total that included 3,523 people and 122 different study groups. For each study, they wrote down important details like how long it lasted, what people had to do (like collect samples), and how many people finished versus quit.
The researchers used special statistical methods to combine information from all these studies together. They looked for patterns—did certain study features predict whether people would drop out? They also checked each study for quality problems using a standard checklist that experts use to evaluate research.
Understanding why people quit diet studies is important because it helps researchers design better studies in the future. If we know what makes people drop out, we can change those things to keep more people involved. This means better research results and better information for doctors trying to help people with inflammatory bowel disease through diet.
This is a systematic review, which is one of the strongest types of research because it combines information from many studies. The researchers followed strict rules about which studies to include and used standard tools to check study quality. They looked at over 3,500 people across 62 studies, which is a large amount of data. However, the studies they reviewed were published over many years, so study methods may have changed over time. The researchers also noted that some studies didn’t report all their information clearly, which could affect the results.
What the Results Show
The main finding is that 84 out of every 100 people (84%) who start these diet studies actually finish them. This is considered a high completion rate in medical research. However, this number dropped to 75 out of 100 (75%) when studies required people to collect stool samples. Studies that lasted 4-8 weeks also had lower completion rates compared to shorter or longer studies.
Interestingly, studies published in the last 10 years had lower completion rates than older studies. This might mean that newer studies are more demanding or that people today have busier schedules. The researchers found that the most important factor affecting whether people quit was having to do complicated things like stool collection—not the length of the study or other factors.
The study also found that studies with very good methods for handling missing data (when people don’t complete all the required tasks) actually had lower completion rates. This seems backwards, but it might mean that studies with stricter rules about missing data are harder for people to complete.
The researchers looked at different types of studies and found that the variation in completion rates between different studies was less than 15%. This means that most studies had similar completion rates, even if they were designed differently. They also found no clear pattern between how long a study lasted and whether people finished it—some short studies had low completion rates and some long studies had high completion rates.
This is one of the first studies to look at why people quit diet studies specifically for inflammatory bowel disease. Previous research on other types of medical studies has shown that complicated procedures and longer studies tend to have more dropouts, and this study confirms that pattern. However, the finding that newer studies have lower completion rates is newer information that hadn’t been clearly documented before.
The researchers could only look at information that was published in studies—if studies didn’t report their completion rates clearly, they couldn’t include that information. Some studies may have had incomplete reporting. The studies reviewed were done over many years with different methods, so comparing them isn’t always like comparing apples to apples. The researchers couldn’t always tell why people quit—they only knew that they did. Finally, all the studies looked at were in English, so results might not apply to studies in other languages or other countries.
The Bottom Line
If you have inflammatory bowel disease and are considering joining a diet study, you should know that most people successfully complete these studies (moderate confidence). However, if a study requires stool collection or lasts 4-8 weeks, be prepared that it might be more challenging to complete (moderate confidence). Talk with the research team about what’s involved before joining, and ask if they can make the process easier for you.
This information is most relevant for people with inflammatory bowel disease who are thinking about joining diet studies. It’s also important for doctors and researchers designing these studies, as it shows them what makes studies harder to complete. People with other digestive conditions might find this helpful too, though the results are specific to IBD.
Completion of these studies typically takes anywhere from a few weeks to several months depending on the study design. Most people who start these studies finish them within the planned timeframe (usually within 1-3 months for the studies reviewed).
Want to Apply This Research?
- If using an app to track participation in a diet study, set weekly reminders for any required tasks (like stool sample collection) and log completion each time. Track your motivation level on a 1-10 scale weekly to catch any drops in commitment early.
- Break down study requirements into smaller, manageable daily tasks rather than thinking about the whole study at once. If stool collection is required, set a specific day and time each week to do it, making it part of your routine like brushing your teeth.
- Use the app to track which study tasks are easiest and hardest for you. Share this feedback with the research team—they may be able to adjust how you do tasks to make them easier. Monitor your overall study completion progress with a visual tracker (like a progress bar) to stay motivated.
This research summary is for educational purposes only and should not be used to make medical decisions. If you have inflammatory bowel disease and are considering dietary changes or participating in research studies, please consult with your doctor or gastroenterologist first. The findings in this study apply to research participation, not to the effectiveness of specific diets for treating IBD. Always discuss any new diet or health intervention with your healthcare provider before starting.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.