Development and validation of the Food Expectation Questionnaire (FEX-Q) to assess food-related perceptions and symptom expectations

This study describes the development and validation of the Food Expectation Questionnaire (FEX-Q), a reliable 44-item instrument using food images that successfully measures individual food-related symptom expectations in patients with irritable bowel syndrome (IBS) and demonstrates strong validity for use in personalized dietary management.

The Gist

Imagine your gut and your brain are like two roommates who are constantly texting each other. Sometimes, the brain sends a message saying, "That pizza looks dangerous! I bet it's going to make you feel sick!" Even before you take a bite, your brain has already started preparing for a disaster. This is especially true for people with Irritable Bowel Syndrome (IBS), where the gut is extra sensitive.

For a long time, doctors knew that what you eat matters, but they didn't have a good way to measure what you think about what you eat. They needed a tool to ask: "When you look at a picture of a burger, how scared is your stomach going to be?"

That's exactly what this paper is about. The researchers created a new tool called the FEX-Q (Food Expectation Questionnaire). Think of it as a "Fear-o-Meter" for food.

How They Built the "Fear-o-Meter"

1. The Sketch Phase (Focus Groups)
First, the team (doctors, dietitians, and researchers) gathered a bunch of food photos. They showed these to people with IBS and asked, "Do you recognize this? Does it look like something that would hurt your tummy?"

• The Analogy: Imagine trying to build a menu for a restaurant, but you keep getting complaints that the picture of the "Spicy Tacos" looks like a "Mild Salad." They had to swap out confusing pictures and add new ones until everyone agreed, "Yes, that is definitely a spicy taco, and yes, it looks scary."

2. The Test Drive (Face-to-Face Validation)
Next, they sat down with 20 people (some with IBS, some without) and had them look at the photos on a computer. They asked, "What do you think this question means?"

• The Fix: They realized that when people were asked about "emotions," they were actually just talking about "taste." So, they swapped that question for a better one: "How likely are you to actually eat this?"
• The Result: They ended up with a final list of 44 food pictures. For each picture, the user rates six things on a scale of 0 to 100:
  • How much do you like the taste?
  • How bad do you think your stomach will hurt? (The most important one!)
  • How likely are you to eat it?
  • How healthy does it look?
  • How fatty does it look?
  • How many carbs does it look like it has?

3. The Big Exam (The Online Survey)
Finally, they sent this questionnaire out to over 260 people across Sweden (134 with IBS and 126 without). They wanted to see if the tool worked as intended.

Did the "Fear-o-Meter" Work?

The results were like a perfect report card:

• It Spots the Difference (Known-Groups Validity):
  When looking at the same picture of a bowl of beans, the people without IBS thought, "Meh, maybe a little gas." But the people with IBS thought, "Oh no, that's going to be a disaster!" The tool successfully separated the two groups. The IBS group expected much worse symptoms (average score of 50) compared to the control group (average score of 18).

• It's Not Just Guessing (Construct Validity):
  The researchers checked if people could actually guess the fat and carbs in the photos.

  • The Analogy: If you show someone a picture of a greasy burger, do they think it's high in fat? Yes! The tool showed that people's "gut feelings" about fat and carbs matched the actual nutritional facts. This proves they were paying attention and using their real-world knowledge, not just clicking randomly.

• It Matches Real Life (Convergent Validity):
  The people who scored high on "expecting pain" also scored high on other tests that measure how bad their actual stomach pain is and how much their diet ruins their quality of life. The tool is talking the same language as the patients' real experiences.

• It's Consistent (Reliability):
  If you split the test in half and checked the answers, they matched up perfectly. It's a stable, reliable tool.

Why Does This Matter?

Think of the FEX-Q as a translator between the patient's brain and the doctor's clipboard.

Before this, if a patient said, "I'm scared to eat onions," a doctor might just say, "Okay, don't eat onions." But with the FEX-Q, the doctor can see how scared the patient is, which specific foods trigger that fear, and why (is it the fat? the carbs? the memory of a bad experience?).

The Bottom Line:
This paper introduces a new, reliable way to measure the "scary thoughts" we have about food. It helps us understand that for people with IBS, the fear of a symptom can be just as powerful as the symptom itself. Now, doctors have a better map to help patients navigate their diets, not just by avoiding foods, but by understanding and managing their expectations.

Technical Summary

1. Problem Statement

• Clinical Context: Food-related gastrointestinal (GI) symptoms are highly prevalent in patients with Irritable Bowel Syndrome (IBS). While dietary modifications (e.g., low FODMAP diet) are standard treatments, the mechanisms linking food exposure to symptoms are not fully understood.
• The Gap: Symptom perception in IBS is influenced by the gut-brain axis, where cognitive expectations and psychological factors (anxiety, prior negative experiences) can amplify visceral signals. However, no validated instrument existed to systematically measure:
  • Food-related symptom expectations.
  • Perceived nutritional characteristics (fat, carbohydrates).
  • Emotional and sensory responses to specific food images in IBS patients versus controls.
• Objective: To develop and validate the Food Expectation Questionnaire (FEX-Q), a standardized, image-based digital tool to quantify these perceptions.

2. Methodology

The study followed a rigorous, stepwise development and validation process involving two distinct phases:

A. Development Phase

• Item Generation: A multidisciplinary team (gastroenterologists, dietitians) selected an initial pool of 48 food images representing "trigger foods" (high FODMAP, high fat), "safe foods," and culturally relevant Swedish items.
• Focus Group Interviews: Ten IBS patients reviewed the images to ensure relevance, leading to the replacement of 8 images and addition of 3, resulting in 51 images.
• Face-to-Face Validation (Qualitative):
  • Participants: 20 adults (6 IBS, 14 controls).
  • Procedure: Cognitive probing was used to assess food recognition, question interpretation, and symptom rationale.
  • Refinement: Items with recognition rates <70% were removed. The "emotional response" item was found to overlap conceptually with "taste preference" and was removed from the final core set. A new item, "Willingness to eat," was added.
  • Final Structure: The finalized FEX-Q consists of 44 food images, each rated on a Visual Analogue Scale (VAS, 0–100) across six domains:
    1. Taste preference.
    2. Expected GI symptom severity (Core item).
    3. Willingness to eat.
    4. Perceived healthiness.
    5. Perceived fat content.
    6. Perceived carbohydrate content.
  • Note: A parallel version for healthcare professionals was also created.

B. Online Validation Phase (Quantitative)

• Participants: 260 adults recruited nationwide in Sweden (134 IBS patients, 126 non-IBS controls).
• Instruments: Participants completed the FEX-Q alongside validated measures:
  • GI Symptom Rating Scale (GSRS) & IBS-SSS.
  • Hospital Anxiety and Depression Scale (HADS).
  • Food-related Quality of Life (FR-QOL).
  • Nine-Item Avoidant/Restrictive Food Intake Disorder Screen (NIAS).
• Data Quality Control: Strict exclusion criteria were applied for missing data (>10%), inconsistent pain reporting across scales, and implausibly fast completion times (<5 sec/question).
• Statistical Analysis:
  • Known-groups validity: Mann–Whitney U tests comparing IBS vs. controls.
  • Construct validity: Spearman correlations between perceived nutrient ratings and objectively calculated nutrient data (via Dietist XP software).
  • Convergent validity: Correlations between FEX-Q scores and clinical/psychological measures.
  • Reliability: Split-half reliability (1,000 random splits) adjusted via the Spearman–Brown prophecy formula.

3. Key Results

Psychometric Properties

• Known-Groups Validity: The FEX-Q successfully distinguished between IBS patients and controls.
  • Symptom Expectation: IBS patients reported significantly higher expected symptom severity (Mean: 50.1) compared to controls (18.4).
  • Willingness to Eat: IBS patients were less willing to eat the foods (55.5 vs. 67.2).
  • No Difference: Groups did not differ significantly in perceived fat or carbohydrate content, indicating the tool measures expectations rather than a fundamental inability to estimate nutrition.
• Construct Validity: Strong correlations were found between perceived and actual nutrient content:
  • Perceived vs. Actual Fat: r = 0.78 (p<0.001).
  • Perceived vs. Actual Carbohydrates: r = 0.59 (p<0.001).
• Convergent Validity: Mean symptom expectation scores correlated significantly with:
  • GI Symptom Severity (GSRS): r = 0.42 (p<0.001).
  • Food-related Quality of Life (FR-QOL): r = -0.39 (p<0.001).
  • Psychological distress (HADS, PHQ) and eating anxiety (NIAS).
• Reliability: High internal consistency was demonstrated via split-half reliability:
  • Spearman–Brown corrected r = 0.88 for both IBS and control groups.

Qualitative Findings

• Participants based symptom expectations on identifiable food characteristics (FODMAPs, fat, portion size) and prior experiences, confirming content validity.
• The "emotional response" item was successfully removed due to high correlation with taste preference, streamlining the instrument.

4. Key Contributions

1. First Validated Tool: The FEX-Q is the first psychometrically validated instrument specifically designed to measure food-related symptom expectations using visual stimuli.
2. Multidimensional Assessment: Unlike traditional dietary logs, it captures the cognitive, emotional, and sensory dimensions of food perception simultaneously.
3. Robust Validation: The study utilized a mixed-methods approach (qualitative focus groups + large-scale quantitative validation) and demonstrated strong validity across known-groups, construct, and convergent metrics.
4. Clinical Utility: The tool provides a quantifiable metric for the "gut-brain" cognitive component of IBS, which is often difficult to measure objectively.

5. Significance and Future Implications

• Mechanistic Insight: The FEX-Q allows researchers to isolate the role of expectation in symptom generation, helping to disentangle physiological triggers from cognitive amplification in the gut-brain axis.
• Personalized Management: By identifying specific foods that trigger high symptom expectations in individual patients, clinicians can tailor dietary counseling and cognitive-behavioral interventions more effectively.
• Research Applications: The tool is designed for use in neuroimaging studies (to correlate food images with brain activation) and large-scale cross-sectional studies.
• Provider-Patient Gap: The existence of a parallel healthcare professional version allows for future research into the discrepancy between what doctors think patients will experience and what patients actually expect, potentially improving clinical communication.

Limitations Noted: The study is cross-sectional (no causality), the food image set cannot cover every possible food, and external validation in independent cohorts is recommended.

Conclusion: The FEX-Q is a reliable, valid, and clinically relevant tool that fills a critical gap in IBS research by quantifying food-related symptom expectations, paving the way for deeper understanding of the gut-brain axis and improved personalized dietary management.