White kidney bean extract and weight in people and animals
What it found
In people, white kidney bean extract led to an average weight loss of 2.6 kg across short to medium term studies, but results varied and some studies found no difference from placebo.
Animal studies also showed reduced weight gain and improved blood markers.
What they found
Studies in people
Weight loss in people
Across human studies, the average weight loss was 2.6 kg, ranging from 1.8 to 3.5 kg. Some studies found no significant difference from placebo, but most showed greater weight loss with the extract.
Body composition in people
Some studies found reductions in body fat, waist circumference and BMI with white kidney bean extract, but others found no significant changes in body fat or lean mass.
Blood markers in people
Effects on blood glucose, triglycerides and cholesterol were mixed. One study found a 34% reduction in the glycemic index of white bread when 3000 mg of powdered extract was added, but other studies found no improvements in fasting glucose or lipids.
Side effects
No significant side effects were reported in human studies lasting up to 84 days, or up to 365 days in one open-label trial. Blood markers, kidney and liver function, and gastrointestinal symptoms were not adversely affected.
Animal and lab studies
Weight and blood markers in animals
Several animal studies found reduced weight gain, lower blood glucose, insulin, triglycerides and cholesterol with white kidney bean extract. However, not all animal studies showed weight reduction.
Gut bacteria in animals
In mice and rats, the extract changed gut bacteria composition, increasing health-associated bacteria like Bifidobacterium and Akkermansia, and increased short-chain fatty acid production.
What the authors conclude
“The evidence presented in this review indicates that WKBE aids weight loss, inducing small (average −2.6 kg) but potentially meaningful reductions in body weight in humans on a short- to medium-term basis (28 to 84 days) compared with a placebo, particularly when consumed alongside a high-carbohydrate diet.”
Also in their conclusions
- They conclude that white kidney bean extract aids weight loss, inducing small but potentially meaningful reductions in body weight in humans on a short- to medium-term basis, particularly when consumed alongside a high-carbohydrate diet.
- They advise that longer duration randomised controlled trials are needed to establish whether similar or greater effects are apparent with more protracted supplementation periods.
- They suggest that future studies should explore combining white kidney bean extract with other bioactive compounds and establishing acceptable and effective vehicles for its provision, such as cereal bars or incorporation into high-carbohydrate meals.
How it was done
The authors note that obesity is rising globally and that current weight-loss strategies like diet, exercise, drugs and surgery have limited success or side effects. They suggest that bioactive compounds from foods, like white kidney bean extract, could be a low-cost, low-burden addition to weight management.
They reviewed human and animal studies on white kidney bean extract. Human studies typically involved overweight or obese people, with doses from 445 to 3000 mg per day, lasting 28 to 84 days, and sample sizes from 10 to 120. Animal studies used mice and rats, with doses from 500 mg/kg to 4 g/kg, lasting 14 to 238 days.
What it can’t tell you
- Most human studies lasted only 28 to 84 days, so the long-term effects of white kidney bean extract are not known.
- The studies used different doses, preparations and populations, making it hard to generalise the results.
- Animal studies cannot show what happens in people, and the gut bacteria findings have not been studied in humans.
Who paid
- Conflicts
- The authors declare no conflicts of interest.
- Authors work at
- Newcastle University, UK; University College Dublin, Ireland
The paper
- Title
- It's No Has Bean: A Review of the Effects of White Kidney Bean Extract on Body Composition and Metabolic Health
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Nolan R, Shannon OM, Robinson N, Joel A, Houghton D, Malcomson FC (2020). It's No Has Bean: A Review of the Effects of White Kidney Bean Extract on Body Composition and Metabolic Health. Nutrients. doi:10.3390/nu12051398Free full textPubMed 32414090DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error