Is severe carbohydrate restriction necessary for appetite suppression? The ASKED randomized controlled trial

Objective

This trial aimed to compare three low-energy diets (LEDs) with different amounts of carbohydrates (CHO) on ketosis and changes in hunger feelings in adults with obesity.

Methods

A total of 101 adults (51 female) with obesity (BMI, mean [SEM], 34.7 [0.4] kg/m²) were randomized to follow three isocaloric LEDs (1000 kcal/day) for 8 weeks, containing either low, medium, or high CHO (70, 100, and 130 g/day, respectively), and 4 weeks of refeeding and weight stabilization. Body weight (BW) and composition, hunger and other appetite ratings, concentrations of β-hydroxybutyrate (βHB), and appetite-related hormones were measured at baseline and at the end of weeks 8 and 12.

Results

At week 8, weight loss and βHB concentrations were significantly different among groups: Low CHO group versus Medium CHO group (BW: 2.32 [0.95] kg, 95% CI: 0.44 to 4.21, p = 0.016; βHB: −0.40 [0.09] mM, 95% CI: −0.67 to −0.09, p < 0.001); Low CHO group versus High CHO group (BW: 2.29 [0.96] kg, 95% CI: 0.39 to 4.19, p = 0.016; βHB: −0.644 [0.10] mM, 95% CI: −0.84 to −0.44, p < 0.001); and Medium CHO group versus High CHO group (BW: −0.03 [0.94] kg, 95% CI: −1.89 to 1.84, p = 0.977; βHB: −0.15 [0.08] mM, 95% CI: −0.30 to 0.002, p = 0.054). No significant differences in hunger were found among groups: Low CHO group versus Medium CHO group (−10.87 [5.92] mm, 95% CI: −0.82 to 22.57, p = 0.068); Low CHO group versus Medium CHO group (7.74 [7.36] mm, 95% CI: −6.77 to 22.26, p = 0.294); and Medium CHO group versus High CHO group (−3.13 [7.48] mm, 95% CI: −17.89 to 11.63, p = 0.676).

Conclusions

Although the findings of this trial are not definitive, changes in hunger ratings with weight loss did not differ among groups. Additional studies with CHO intake of up to 130 g in 1000-kcal/day LEDs are warranted to replicate these findings.