Obese individuals are at increased risk of type 2 diabetes compared to their healthy weight counterparts. Dietary fibre, such as alginate, could attenuate glycaemic disturbances associated with obesity when included in the diet.Forty self-reported, healthy males completed this randomised, single-blinded, controlled, parallel trial to determine the glycaemic response to a controlled test-lunch of mixed composition following an ionic-gelling alginate preload drink compared to an acidic-gelling control.Individual baseline area under the curve was 52% lower (p=0.010) and peak glycaemia was 14% lower (p<0.0005) after the ionic-gelling alginate drink compared with the control. Body fatness was a predictor of postprandial glycaemia, however there was no interaction effect between body fat % and treatment type.We have shown ionic-gelling alginate can attenuate glycaemic response to a homogenous fixed load lunch. Functional foods that include ionic-gelling alginates may benefit those with elevated postprandial blood glucose.