Ethanol extracts, dried powders and fibres (total and soluble fibre) of the tropical red algae Kappaphycus alvarezii, Kappaphycus striatus and Eucheuma denticulatum were analysed for their effect on lipase and α-amylase activity using turbidimetric method and dinitrosalicylic acid (DNS) assay, respectively. The nutrient composition analyses were determined using standard methods. The ethanol extract of dried K. striatus (Ks-III) showed the highest reduction in lipase activity with 92 % inhibition followed by seaweed powders (K. alvarezii (Ka-III), K. striatus (Ks-III) and E. denticulatum (Ed-III)) with average inhibition of 60 %. Soluble fibres of K. alvarezii (Ka-V) and E. denticulatum (Ed-V) showed significant inhibition with 60 and 57 % reduction, respectively. Only the ethanol extract of fresh E. denticulatum (Ed-I) showed 88 % inhibition of α-amylase. Nutritional component analyses showed that all three seaweeds are low in crude fat, suggesting the possible use of seaweed as a dietary supplement and for potential weight and glycaemia management.