Oral white kidney bean extract reduces weight by 1.62 kg in adults with overweight or obesity compared to placebo

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Nutrition research (New York, N.Y.) Published June 5, 2026 Medically reviewed June 5, 2026 Study authors: Shi Nan, Wang Ruye, Cao Xinyi, Huang Zanche, Lin Fangxuan, Xu Ruoyi, Zhang Qin PubMed ↗ DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Consider oral white kidney bean extract as a generally well-tolerated adjunct for weight management in adults with overweight or obesity.

This systematic review and meta-analysis assessed the efficacy of oral white kidney bean extract for weight management in adults with overweight or obesity. The analysis included 543 participants and compared the extract against placebo. The primary outcome was weight reduction, with secondary outcomes including body mass index, fat mass, waist, hip, fasting blood glucose, triglycerides, and random insulin.

The pooled results demonstrated a mean difference of -1.62 kg for weight reduction with a 95% CI of -1.99 to -1.25. Body mass index reduction showed a mean difference of -0.58 kg/m² with a 95% CI of -0.73 to -0.43. Fat mass reduction was -1.17 kg with a 95% CI of -1.80 to -0.55. Waist circumference decreased by -1.58 cm (95% CI -2.19 to -0.96) and hip circumference by -0.99 cm (95% CI -1.94 to -0.05). No significant difference was observed for fasting blood glucose, triglycerides, or random insulin.

Safety data were not reported, though the extract was generally well-tolerated with no serious adverse events. The authors state that further large-scale, high-quality, and long-term trials are warranted to confirm efficacy and clarify its potential role in metabolic health. This suggests the extract may serve as a generally well-tolerated, nonpharmacological adjunct for weight management pending confirmation.

Study Details

Study typeMeta analysis

Sample sizen = 543

EvidenceLevel 1

PublishedJun 2026

PMID42066439

View Original Abstract ↓

The global prevalence of overweight and obesity has risen sharply in recent decades, becoming a major public health concern. White kidney bean (Phaseolus vulgaris L.) extract (WKBE), rich in α-amylase inhibitors, may delay carbohydrate digestion and reduce energy intake. We hypothesized that WKBE could significantly improve key anthropometric outcomes in adults with overweight and obese compared with placebo, with acceptable safety. To test this hypothesis, we systematically searched four databases from inception to January 31, 2026, for randomized controlled trials of oral WKBE. Eight randomized controlled trials (n = 543) met the inclusion criteria. Random-effects meta-analyses showed reductions in weight (MD -1.62 kg, 95% confidence interval [CI] -1.99 to -1.25), body mass index (MD -0.58 kg/m², 95% CI -0.73 to -0.43), fat mass (MD -1.17 kg, 95% CI -1.80 to -0.55), waist (MD -1.58 cm, 95% CI -2.19 to -0.96), and hip (MD -0.99 cm, 95% CI -1.94 to -0.05) (all P < .05). No significant differences were observed in fasting blood glucose, triglycerides, or random insulin. No serious adverse events related to WKBE were reported. These findings indicate that WKBE may serve as a generally well-tolerated, nonpharmacological adjunct for weight management. In the future, further large-scale, high-quality, and long-term trials are warranted to confirm its efficacy and clarify its potential role in metabolic health.