About half of scientific studies testing plant-based foods are modifying the standard INFOGEST 2.0 laboratory digestion test, according to Gram Research analysis of 119 studies published between 2019 and 2024. Researchers adjust enzyme levels, stomach acid, bile concentration, and digestion time to better match real human digestion or measure specific nutrients more accurately. While these changes can improve individual studies, they make it harder to compare results across different research, highlighting the need for clearer reporting standards.
Scientists use a special test called INFOGEST 2.0 to see how plant-based foods break down in your stomach and digestive system. A Gram Research analysis of 119 studies found that about half of scientists are making changes to this standard test. They modify things like enzyme levels, stomach acid, and digestion time to better match real human digestion or to track specific nutrients like minerals and antioxidants. While these changes can make tests more realistic, they also make it harder to compare results between different studies. Researchers are calling for better guidelines to keep tests both accurate and consistent.
Key Statistics
A systematic review of 119 studies published between 2019 and 2024 found that 50.4% of plant-based food research modified the standard INFOGEST 2.0 digestion protocol, most commonly adjusting enzyme activity, pH levels, bile concentration, and digestion time.
According to Gram Research analysis of this systematic review, methodological modifications to the INFOGEST 2.0 protocol were driven not only by plant-based food characteristics but also by aging-related physiological conditions, specific experimental needs, and the measurement of particular compounds like minerals and phenolic compounds.
A 2026 systematic review examining 119 plant-based food studies found that while protocol modifications may enhance physiological relevance or analytical accuracy, they introduce a significant trade-off with interstudy comparability, highlighting the need for consensus-based extensions of the INFOGEST framework.
The Quick Take
- What they studied: How scientists are modifying a standard laboratory test (INFOGEST 2.0) that simulates human digestion when studying plant-based foods and supplements
- Who participated: 119 research studies published between 2019 and 2024 that used the INFOGEST 2.0 digestion model with plant-based foods
- Key finding: Approximately 50.4% of studies made changes to the standard test protocol, most commonly adjusting enzyme activity, stomach acid levels, bile concentration, and digestion time
- What it means for you: When you read about plant-based food studies, the results might not be directly comparable because researchers are using slightly different testing methods. This makes it harder to know which findings you can trust across different studies.
The Research Details
Researchers searched three major scientific databases (ScienceDirect, Scopus, and PubMed) for studies published between 2019 and 2024 that used the INFOGEST 2.0 protocol with plant-based foods. They found 119 studies that met their criteria. The INFOGEST 2.0 protocol is a laboratory test that mimics how food moves through your mouth, stomach, and small intestine, it’s like a fake digestive system in a test tube. The researchers carefully examined each study to identify what changes scientists made to this standard test and why they made them.
The team organized all the modifications they found into three categories based on which part of digestion was changed: the mouth phase, the stomach phase, and the small intestine phase. They looked at what specific parameters were altered (like how much enzyme was used or how acidic the stomach simulation was) and tried to understand the reasons behind each change. Some changes were made because scientists wanted to better match what happens in real human bodies, while others were made to measure specific nutrients more accurately.
Having a standard test is important because it lets scientists compare their results fairly. If everyone uses the same recipe for the fake digestive system, then when one study finds that a plant-based food releases more nutrients than another study, you know it’s because of the food, not because they used different testing methods. When scientists start changing the recipe, it becomes harder to trust comparisons between studies.
This is a systematic review, which is a high-quality type of research that carefully examines many other studies. The researchers used established databases and clear search methods, making their work reliable. However, the original studies they reviewed varied in quality and methods, which is exactly why this review was needed. The findings show that the field needs better standards and clearer communication about what changes are being made and why.
What the Results Show
According to Gram Research analysis of this systematic review, about half of all studies (50.4%) made modifications to the standard INFOGEST 2.0 protocol. The most common changes involved adjusting enzyme activity levels, changing the pH (acidity) of the stomach simulation, altering bile concentration, and modifying digestion time. These weren’t random changes, researchers had specific reasons for making them.
The modifications fell into several categories. Some scientists adjusted the test to better match what happens in older adults’ digestive systems, since aging changes how digestion works. Others made changes to track specific nutrients they were interested in, like minerals or phenolic compounds (plant chemicals with health benefits). Some researchers modified the test based on what they needed to measure or blank subtraction requirements (removing background noise from their measurements).
Interestingly, the researchers found that these modifications weren’t driven solely by the plant-based nature of the foods being tested. Instead, they reflected a mix of factors including the study’s goals, the population being studied, and the specific nutrients being measured. This suggests that scientists are thoughtfully adapting the test, but without a unified framework for doing so.
The review identified that modifications occurred across all three phases of digestion, oral, gastric, and intestinal. Different studies prioritized different changes based on their research questions. Some focused on making the test more physiologically relevant (closer to real human digestion), while others prioritized analytical accuracy (measuring nutrients more precisely). The researchers noted that while these adaptations can improve the quality of individual studies, they create a significant problem: it becomes difficult to compare results across different studies because each one is using a slightly different testing method.
The INFOGEST 2.0 protocol was created to standardize how scientists test food digestion in the laboratory. This systematic review is the first comprehensive examination of how much scientists are actually deviating from this standard in plant-based food research. Previous work established the protocol, but this review reveals that real-world application is more variable than the original framework anticipated. This finding suggests the field has evolved beyond a one-size-fits-all approach, but now needs better guidelines.
This systematic review examined published studies, so it only captures what researchers chose to report. Some modifications might not have been clearly described in papers. The review focused on plant-based foods specifically, so findings may not apply to other food types. Additionally, the review didn’t evaluate whether specific modifications actually improved the quality of results, it just documented what changes were made. Finally, the original studies varied widely in quality and design, which affects how much we can generalize from the findings.
The Bottom Line
If you’re reading studies about plant-based foods, look carefully at the methods section to see if the researchers used the standard INFOGEST 2.0 protocol or made modifications. When comparing results between studies, be cautious about drawing firm conclusions if they used different testing methods. For researchers: adopt clearer reporting practices when modifying the protocol and work toward consensus-based extensions of INFOGEST that balance real-world accuracy with consistency. Confidence level: High: this recommendation is based on a comprehensive review of current practices.
This matters most to researchers studying plant-based foods, nutritionists interpreting food science studies, and companies developing plant-based products. It’s also relevant to anyone reading nutrition news and wanting to understand how reliable the studies are. If you’re making dietary decisions based on plant-based food research, understanding this issue helps you evaluate which studies are most trustworthy.
This isn’t about personal health timelines, it’s about scientific progress. The field needs to develop better standards over the next 1-2 years. Once clearer guidelines exist, future studies will be more comparable, making it easier to trust nutrition research in 2-3 years.
Frequently Asked Questions
How do scientists test if plant-based foods are healthy?
Scientists use laboratory tests like INFOGEST 2.0 that simulate human digestion in a test tube. The test mimics how food moves through your mouth, stomach, and small intestine to see which nutrients are released and absorbed.
Why do different plant-based food studies give different results?
About 50% of studies modify the standard testing protocol to better match real digestion or measure specific nutrients. These variations make direct comparisons difficult, even when studying similar foods.
Should I trust plant-based food research studies?
Yes, but with awareness. Check if studies clearly describe their testing methods. Studies using the standard protocol or clearly justified modifications are generally more reliable and comparable to other research.
What changes do scientists make to the digestion test?
Common modifications include adjusting enzyme levels, changing stomach acid concentration, altering bile amounts, and changing digestion time. Scientists make these changes to match specific populations (like older adults) or to measure particular nutrients more accurately.
Will plant-based food research get more consistent?
Researchers are calling for better standards and clearer guidelines. As the field develops consensus-based extensions of the INFOGEST protocol, future studies should become more comparable and easier to interpret.
Want to Apply This Research?
- Track which plant-based food studies you read and note whether they mention using the standard INFOGEST 2.0 protocol or modifications. Rate your confidence in each study’s findings (high/medium/low) based on methodology transparency.
- When evaluating plant-based food claims, use the app to check if supporting studies clearly describe their testing methods. Prioritize studies that explicitly state they followed standard protocols or clearly justify their modifications.
- Create a folder in the app for ‘Plant-Based Food Research’ and save studies you encounter. Over time, you’ll notice patterns in which research is most reliable and comparable, helping you make better-informed dietary choices.
This article summarizes a systematic review of laboratory testing methods for plant-based foods. It does not provide medical advice or nutritional guidance. The findings relate to how scientists test foods in laboratories, not to the health effects of plant-based diets. If you have specific health concerns or dietary questions, consult a registered dietitian or healthcare provider. Individual study results may vary based on methodology, and more standardized research is needed to draw firm conclusions about plant-based food nutrition.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
