PurposeThe purpose of this study is to evaluate the chemical composition of unripe banana flour from Southeast Brazil and verify its nutritional, physiological and biochemical properties in adult Wistar rats.Design/methodology/approachAnalysis of soluble solids, titratable acidity, pH, moisture, ash, lipids, proteins, carbohydrate, resistant and total starch and energy was obtained. In all, 18 male Wistar rats were given different concentrations of unripe banana flour (0, 10 and 20 per cent) and these assessments were performed: feed, caloric and water intake; weight gain; coefficient of food efficiency; weight of organs; body, tibia and femur length; total mineral of bones; and biochemistry of blood, hepatic fluids and feces.FindingsUnripe banana flour showed a potential for weight control as well as increased fecal cholesterol excretion. These results showed the potential of unripe banana flour for obesity treatment and lipid excretion. Nevertheless, plasma triacylglycerol levels increased in the animals that received the largest amount of banana flour (20 per cent w/w), possibly because of the large amount of resistant starch in the flour, indicating the need for additional studies to confirm the mechanisms responsible for this increase.Originality/valueUnripe banana flour may promote beneficial health effects (such as weight control and increased elimination of cholesterol in feces); however, the large amount of resistant starch present may be responsible for an increase in blood triacyglycerol.