Effects of isocaloric (sweetness differences but constant calories) preloads and isosweet (caloric differences but constant sweetness) preloads, as well as preloads that were neither isosweet nor isocaloric (sweetness and caloric differences) on subsequent ad libitum meal and total (preload + ad libitum) energy intakes were investigated. Thirty-five crossover studies were eligible for inclusion, representing 116 comparisons (41, isocaloric; 41, isosweet; and 34, neither isosweet nor isocaloric). References of existing reviews and literature from 4 databases were searched. The calculated raw mean differences in ad libitum and total energy intakes were pooled in meta-analyses using a random-effects model and the inverse of the variance as the weighting factor. Energy intakes at an ad libitum meal were significantly lower for low-/no-calorie sweetener (LNCS)-sweetened compared with unsweetened preloads in the isocaloric comparison (-55.5 kcal; 95% CI: -82.9, -28.0 kcal; P < 0.001); however, the difference in energy intake was not significant in additional sensitivity analyses (i.e., removal of comparisons where the matrix was a capsule and when xylitol was the LNCS). For the isosweet comparison, although the pooled energy intake at the ad libitum meal was significantly greater with the LNCS-sweetened preload compared with the caloric sweetener (CS)-sweetened preload (58.5 kcal; 95% CI: 35.4, 81.7 kcal; P < 0.001), the pattern was reversed when total energy intake was considered (-132.4 kcal; 95% CI: -163.2, -101.6 kcal; P < 0.001), explained by only partial compensation from the CS-sweetened preload. The results were similar when assessing ad libitum and total energy intakes when unsweetened compared with CS-sweetened preloads were consumed. Unsweetened or LNCS-sweetened preloads appear to have similar effects on intakes when compared with one another or with CS-sweetened preloads. These findings suggest that LNCS-sweetened foods and beverages are viable alternatives to CS-sweetened foods and beverages to manage short-term energy intake.
The present systematic review and meta-analysis of randomised controlled trials (RCTs) supports the assertion that the consumption of low/no calorie sweetened in place of sugar-sweetened foods and beverages leads to lower short-term energy intake by, on average, 130 calories. This finding confirms that low/no calorie sweetened options are viable alternatives to caloric-sweetened foods and beverages to manage short-term energy intake.
The study analysed thirty-five crossover RCTs including 116 comparisons. Separate meta-analyses were conducted to compare the effects on energy intakes of: 1) isocaloric test food (preload) options (e.g. water vs low/no calorie sweeteners, where sweetness differs but calories are equal), 2) isosweet preload options (e.g. sugar vs sweeteners, where calories differ but sweetness is the same), and 3) preload options that were neither isosweet nor isocaloric (e.g. sugar vs water, where both sweetness and calories differ).
For the sugar vs sweeteners comparison (isosweet preloads), the results indicated that total energy intake is significant lower by approx. 130 calories with low/no calorie sweeteners versus caloric- sweetened preloads such as sugar.
For the water vs sweeteners comparison (isocaloric preloads), the results indicated that low/no calorie sweeteners have at least a similar effect on acute energy intake to unsweetened preloads such as water and do not increase caloric intakes relative to unsweetened preloads.
For the water vs sugar comparisons (neither isosweet nor isocaloric preloads), the results were similar with the sweeteners vs sugar comparisons, indicating that total energy intakes were significantly lower with unsweetened versus caloric-sweetened preload consumption.
Overall, the findings of this study support the assertion that both unsweetened (e.g. water) and low/no calorie sweetened foods and beverages may benefit body weight and glycemic control by limiting calorie intake, when used to replace sugar-sweetened foods and beverages. A second conclusion is that, since both unsweetened and low/no calorie sweetened options had a similar result on caloric intake, sweetness per se does not affect appetite or acute energy intake.