Eating veg, protein before carbo blunts glycaemic spike after meal
Eating vegetable and protein before carbohydrate attenuated postprandial glucose response in healthy Asian adults, according to the PATTERN* study, suggesting that behavioural change in eating sequence may be a potential strategy for modulating glycaemic response.
“Our findings provide a simple but effective way to reduce postprandial glucose and prevent type 2 diabetes,” suggested the researchers led by Professor Christiani Jeyakumar Henry from the Department of Biochemistry at National University of Singapore.
The crossover meal trial included 16 healthy participants (mean age 25.8 years, 81 percent male) who consumed five experimental isocaloric meals across five study sessions, separated by a washout period of 1 week between sessions. The sequence of food intake was different in each session, and participants were randomized to start with any of the following intake sequence (before crossing over to the other intake sequence): vegetables first before concurrent meat and rice (V-MR), meat first before concurrent vegetables and rice (M-VR), vegetables first, followed by meat and then rice (V-M-R), concurrent vegetables, meat and rice (VMR), and rice before concurrent vegetables and meat (R-VM). [Clin Nutr 2019;doi:10.1016/j.clnu.2019.04.001]
Overall, postprandial glucose response was significantly different among the different food intake sequences (p<0.001). Among the five different intake sequences, R-VM produced the greatest glucose spike within 30 minutes after a meal.
Compared with the R-VM pattern, the rise in postprandial blood glucose levels was attenuated in the other four intake sequences, with the smallest rise at 30 minutes with V-M-R (p<0.05), followed by V-MR (p<0.05) and M-VR (p<0.05).
Postprandial serum insulin response was also significantly lower within the first hour after V-M-R (iAUC**, 46.27 mmol/L x min) compared with M-VR (iAUC, 69.69 mmol/L x min), VMR (iAUC, 98.63 mmol/L x min; p<0.05), and R-VM (iAUC, 135.14 mmol/L x min; p<0.05).
Among the five eating patterns, release of the incretin hormone GLP-1*** was greatest after V-M-R and remained so throughout 180 minutes of the study, although postprandial levels of another incretin GIP# did not rise significantly at 30 minutes after meal.
Compared with R-VM, V-MR also showed significantly blunted glycaemic response up to 2 hours postprandial (p<0.05).
“In recent years, the prevalence of diabetes in the Asian population has increased and evidence has indicated that the risk of diabetes in Asians may be higher than that of other racial groups such as Caucasians of the same body mass index,” noted Jeyakumar and co-authors.
“The findings in the present study indicate that eating vegetables, protein before carbohydrate present a simple and novel eating strategy to attenuate postprandial glycaemic response without any compensation of insulin secretion in healthy subjects,” they said.
As gastric emptying rate was not measured in the current study, the researchers could not ascertain whether this was the mechanism mediating the effect eating sequence had on glycaemic and insulinaemic response. Due to difficulty of venous cannulation in female subjects, the study population was predominantly male, which they recognized as a study limitation.