Abstract
With global obesity on the rise, driven in part by high added-sugar consumption, non-caloric sweeteners are proposed to reduce sugar intake. However, limited studies have investigated whether tolerance to sweetness differs between caloric and non-caloric sweeteners across overweight and normal weight groups, a question that is essential for evaluating the feasibility of sugar substitution strategies. This study explores the role of sweet rejection thresholds (RjT) to caloric (i.e., sucrose) and non-caloric (i.e., sucralose) sweeteners on BMI-related high sugar intake. A total of 148 participants (final 105; 18–30 years, females = 63) underwent psychophysical assessments for sucrose and sucralose, in terms of rejection and detection thresholds. Dietary intake was assessed using a Food Frequency Questionnaire to calculate total and added sugar intake, while BMI was calculated from anthropometric measurements. The results revealed an average daily sugar intake was 1263 kJ (16.6 % of total energy), with added sugars at 11.5 %, exceeding the WHO’s recommended 5 % limit. BMI was positively correlated with both total and added sugar intake (r = 0.26–0.38, p < 0.05). Furthermore, participants in the overweight group exhibited higher RjT for sucrose than those with normal weight (F(1,103)= 8.35, p = 0.019), which in turn predicted greater sugar intake; specifically, each unit increase in sucrose RjT corresponded to 19.7 kJ of total sugar and 11.0 kJ of added sugar intake. These findings indicate that tolerance to caloric and non-caloric sweeteners differs, as do their associations with sugar consumption and adiposity, suggesting that substituting non-caloric sweeteners may not fully mirror the patterns observed with caloric sugars.