Method of Food Preparation Influences Blood Glucose Response to a High-Carbohydrate Meal: A Randomised Cross-over Trial

Abstract

The aim of this study was to establish the blood glucose response to different cooking methods of pasta. Participants consumed three identical meals in a random order that were freshly cooked (hot), cooled and reheated. Blood glucose concentrations were assessed before, and every 15 min after ingestion of each meal for 120 min. There was a significant interaction between temperature and time (F ( 8.46 – 372.34 ) = 2.75, p = 0.005), with the reheated (90 min) condition returning to baseline faster than both cold (120 min) and hot conditions. Blood glucose area under the curve (AUC) was significantly lower in the reheated (703 ± 56 mmol·L−1·min−1) than the hot condition (735 ± 77 mmol·L−1·min−1, t ( 92 ) = −3.36, pbonferroni = 0.003), with no significant difference with the cold condition (722 ± 62 mmol·L−1·min−1). To our knowledge, the current study is the first to show that reheating pasta causes changes in post-prandial glucose response, with a quicker return to fasting levels in both the reheated and cooled conditions than the hot condition. The mechanisms behind the changes in post-prandial blood glucose seen in this study are most likely related to changes in starch structure and how these changes influence glycaemic response.

Effect of cooking, 24 h cold storage, microwave reheating, and particle size on in vitro starch digestibility of dry and fresh pasta

“…Although the formation of retrograded starch upon cold storage has been widely reported, there are relatively few studies of re-heated retrograded starch, and current understanding of the starch structural changes and mechanisms that occur under re-heating conditions is limited. A recent human study reported a slightly lower area under postprandial glucose curves following ingestion of reheated pasta compared with freshly cooked pasta, 22 however contrary to what would be expected from the literature on cooling and resistant starch, 32,33 this study found no significant difference between hot and cold pasta. 22 Studies performed on other carbohydrate foods types suggest that refrigeration prior to re-heating reduces starch digestibility and in some case, glycaemic responses.…”

“…A recent human study reported a slightly lower area under postprandial glucose curves following ingestion of reheated pasta compared with freshly cooked pasta, 22 however contrary to what would be expected from the literature on cooling and resistant starch, 32,33 this study found no significant difference between hot and cold pasta. 22 Studies performed on other carbohydrate foods types suggest that refrigeration prior to re-heating reduces starch digestibility and in some case, glycaemic responses. For instance, in a study on parboiled rice, there was a tendency for glycaemic responses to be lower when boiled rice had been refrigerated prior to re-heating, however the difference in the postprandial glycaemic response between freshly cooked and re-heated rice was not statistically significant.…”

“…One human study did not find any significant differences between postprandial glycaemic responses to freshly cooked pasta compared with pasta that was cooked, chilled and then reheated, 21 whereas another study recently reported that re-heated pasta evoked somewhat lower postprandial glycaemic responses compared with freshly boiled pasta, but observed no difference between freshly boiled and refrigerated meals. 22 Furthermore, the mechanistic basis for these observations has yet to be established.…”

Resistant Starch Production and Glucose Release from Pre‐Prepared Chilled Food: The SPUD Project

“…Consuming precooked potatoes, cold, has been shown to elicit a lower glycaemic response than the equivalent freshly cooked potatoes (Leeman et al 2005), whereas no differences were observed between freshly cooked and chilled-reheated boiled potatoes (Fernandes et al 2005). In contrast, a reduction in glycaemic response was observed following a reheated pasta meal in comparison with freshly cooked, with no differences observed for a chilled pasta meal (Hodges et al 2020). Similarly, chilled and reheated white rice elicited a lower glycaemic response than freshly cooked white rice (Sonia et al 2015).…”

Normal Versus Slowly Processed Pasta and Post-Prandial Glucose Homeostasis in Healthy Subjects: A Pilot Study

“…Nutritional science is rapidly growing and widening its horizon by taking into consideration the meal, the “event” of the meal (i.e., time-sequencing strategies and time-restricted feeding [ 3 ]), and the “process” through which the food undergoes, such as for packaged foods. Recently, the importance of food preparation has been pointed out by several observations describing the relevance of domestic attention to these issues to obtain benefits in terms of metabolic response [ 4 , 5 ]. Dietary carbohydrates are the main components of a balanced diet [ 1 ].…”