Potatoes Compared with Rice in Meals with either Animal or Plant Protein Reduce Postprandial Glycemia and Increase Satiety in Healthy Adults: A Randomized Crossover Study.

Background: Rice and pasta are recommended as healthier than potatoes on the basis of their glycemic index when eaten alone.

Objectives: The study objective was to evaluate postprandial glycemia (PPG), appetite, and food intake (FI) at meals with potatoes or rice when consumed with either meatballs or their vegetarian substitute.

Methods: In a randomized, single-blinded, crossover design, 26 (13 males and 13 females) healthy adults (age: 18-45 y; body mass index [kg/m]: 18.5-29.9) consumed isocaloric fixed amounts of either meatballs or vegetarian-substitute balls with ad libitum access to either baked French fries (BFF), instant mashed potatoes (IMPs), or rice (control). FI was measured at the meal and at an ad libitum pizza meal served 120 min later. Blood glucose (BG), appetite, and plasma insulin responses were measured within the meal (0-30 min), postmeal (30-120 min), within pizza meal (120-140 min), and post-pizza (140-170 min). Effects of protein source, carbohydrate (CHO) source, and sex and their interactions were analyzed using analysis of variance followed by Tukey's post hoc test.

Results: Participants consumed 23-25% less treatment meal energy (kcal), 32-34% less CHO energy (kcal), and 13-16% less total energy (kcal) after the BFF and IMP than rice meals (P < 0.0001). Postmeal BG was lower after IMP (6.76 ± 0.15; P < 0.0001) and rice (6.92 ± 0.15; P = 0.0012) compared with BFF (7.19 ± 0.15). Post-pizza BG was higher after rice (6.77 ± 0.09) than that after BFF (6.51 ± 0.09; P = 0.0012) and IMP (6.39 ± 0.09; P < 0.0001). Postmeal meaned insulin was higher after BFF (82.16 ± 8.58) and IMP (77.75 ± 8.60) compared with rice (56.44 ± 8.59; P < 0.002). Insulin during pizza meal was lower after BFF (17.14 ± 6.90) compared with both IMP (39.03 ± 6.90; P = 0.0060) and rice (34.21 ± 6.90; P = 0.0336). Meatballs led to lower BG (6.48 ± 0.09; P = 0.0076) and higher insulin (84.54 ± 5.87; P = 0.0406) post-pizza compared with their plant protein substitute (6.64 ± 0.09 and 73.18 ± 5.87, respectively).

Conclusions: Adults consuming meatballs or plant-based substitute with ad libitum IMP had lower PPG post-treatment and at a later pizza meal compared with rice. Both IMP and BFF resulted in lower energy intake than after rice. This trial was registered at http://clinicaltrials.gov (https://register.

Clinicaltrials: gov/prs/app/action/SelectProtocol?sid=S000CKIJ&selectaction=Edit&uid=U0000IA4&ts=2&cx=-uf51kf) as NCT05610124. Protocol ID: 43406 (Postprandial Glycemia and Satiety of Meals with Potatoes, with and without Protein).