Low-calorie sweeteners along with carbohydrates may decrease insulin sensitivity, finds study.

US: There is a general belief that overconsumption of sugar-sweetened beverages contributes to the prevalence of obesity and related comorbidities such as type 2 diabetes (T2D). Whether a similar relationship exists for no- or low-calorie "diet" drinks is still in a debate.

Researchers from Yale University tested glucose tolerance and taste perception before and after participants consumed seven 355 mL novel-flavoured equi-sweet beverages over 2 weeks using randomized double-blind designs. They demonstrated that consuming seven sucralose-sweetened beverages with, but not without, a carbohydrate over 10 days decreases insulin sensitivity in healthy human participants, an effect that correlates with reductions in the midbrain, insular, and cingulate responses to sweet, but not sour, salty, or savoury, taste as assessed with fMRI. Taste perception was unaltered and consuming the carbohydrate alone had no effect.

Forty-five healthy humans were randomly assigned to consume(1) beverages sweetened with sucralose (sweet uncoupled from calories – LCS),

(2) beverages sweetened with sucrose (sweet coupled with calories – Sugar), or

(3) beverages sweetened with sucralose and combined with maltodextrin (Combo).

Oral glucose tolerance tests (OGTTs) (or single blood draws), sensory tests, and neuroimaging were conducted before and after participants consumed seven of their assigned beverages over 2 weeks in the laboratory. Protocol details and inclusion/exclusion criteria are listed in the STAR Methods. A parallel study was conducted in adolescents since adolescents go through a period of transient insulin resistance.