Fiber2026-06

Acceptability and impact on health-related markers of a sustainable dietary pattern: results from a pilot randomized controlled cross-over study.

Vinelli Valentina, Tucci Massimiliano, Martini Daniela, Rendine Marco et al. — European journal of nutrition

Summary

This pilot study explored how a sustainable, plant-based diet impacts health. Participants significantly increased their fiber intake and showed improvements in markers related to blood sugar regulation, such as fasting insulin. While generally acceptable, the diet required more perceived effort, particularly in preparing plant-based protein sources like legumes.

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Key points

A sustainable, plant-based diet significantly increased participants' fiber intake.
The diet led to improvements in blood sugar regulation, specifically lower fasting insulin levels.
Changes in gut bacteria composition were also observed with the plant-based diet.
While acceptable, participants found the plant-based diet required more effort, especially for meal preparation.

What the study looked at

What question the study asked: Researchers wanted to see if a specific sustainable, plant-based eating plan, called EAT-IT, could be both acceptable to people and positively affect their health markers, especially compared to a typical diet. How it was studied (design/participants): They conducted a small pilot study with nine young adults. Participants followed two different diets for six weeks each: the EAT-IT plan and a control diet based on standard Italian food guidelines. The study was 'randomized controlled cross-over,' meaning participants tried both diets in a random order. Scientists tracked their food intake, body measurements, blood tests for metabolic health, and even changes in their gut bacteria. They also asked participants about their experience with the diets. What it found: The findings showed that the EAT-IT diet led to a notable increase in daily fiber intake. Importantly, participants on the EAT-IT diet experienced a reduction in fasting insulin levels, suggesting improved blood sugar control. Changes in gut bacteria were also observed. While participants generally found the EAT-IT diet acceptable, they reported it required more effort, particularly when preparing plant-based protein sources like beans and lentils.

Dietary takeaway

This study suggests that adopting a more plant-based diet can significantly boost your fiber intake, which may contribute to better blood sugar management. To achieve this, focus on incorporating more fruits, vegetables, whole grains, and legumes into your daily meals. However, remember this was a small pilot study, so these findings need to be confirmed by larger research before making definitive dietary recommendations.

Abstract

PURPOSE: Well-balanced plant-based diets can promote health and reduce environmental impact. However, evidence from interventional studies remains limited. This pilot intervention study aimed to provide exploratory insights into potential challenges associated with the EAT-IT dietary pattern, an adaptation of the EAT-Lancet Healthy Reference Diet. METHODS: Nine subjects (mean age 26 ± 2 years, 5 females) participated in a 6-week randomized controlled cross-over trial. Participants followed two isocaloric interventions: the EAT-IT dietary pattern and a control diet based on the Italian Food-Based Dietary Guidelines. Dietary intake was recorded using 7-day food records. Anthropometric measurements and metabolic parameters were collected according to standardized and validated protocols. Gut microbiota was analyzed through 16 S rRNA gene sequencing and taxonomic profiling. Acceptability was evaluated via a validated questionnaire. RESULTS: Nutritional analysis showed that the EAT-IT pattern significantly increased fiber intake from 11.3 ± 5.2 to 15.1 ± 4.2 g/1000 kcal and ω-6 fatty acid intake from 5.7 ± 2.2 to 6.6 ± 1.9 g/day (p < 0.05 for interaction). Regarding metabolic markers, a significant within-group reduction (p < 0.05) was observed for fasting insulin (8.4 ± 2.2 to 6.5 ± 2.2 µU/mL) and HOMA1-IR (2.0 ± 0.6 to 1.5 ± 0.5). Changes in gut microbiota were also observed, specifically an increase in Bacteroides and a decrease in Coriobacteriaceae. While generally well-accepted, participants reported a higher perceived effort for EAT-IT, particularly regarding legume preparation. CONCLUSION: Despite the small sample size, this pilot study offers relevant insights into key aspects of sustainable plant-based diets, underscoring the necessity for further investigation.

View on PubMed →DOI: 10.1007/s00394-026-04014-7