Many carb-conscious eaters consume low glycemic carbohydrates to minimize fluctuations in insulin levels with the intention to control blood sugar and burn body fat. Existing evidence indicates that the quantity and type of carbohydrate consumed influence blood glucose levels and that the total amount of carbohydrate consumed is the primary predictor of glycemic response. The consumption of low glycemic foods that are rich in fiber has become the basis for popular diets like the South Beach Diet and the Zone Diet. This idea is based on the fact that insulin helps with fat storage—thus having fewer spikes in insulin can enhance fat utilization. A new study published in the Journal of Diabetes Care reports that the food order of your meal may also impact the glycemic load of a meal. The researchers found that the absorption of carbohydrates is somehow slowed down by eating vegetables, which are low on the glycemic index.
Researchers reported that when overweight people with type 2 diabetes ate vegetables and proteins first, their blood sugar levels were about 29 percent lower 30 minutes after starting the meal, compared to when they ate the carbs first. The researchers recruited 11 people with type 2 diabetes who were all overweight or obese. They were also taking a drug called Metformin, which helps to control blood sugar.The participants all fasted for 12 hours overnight before consuming a 628 calorie meal with protein, carbohydrates, and fat. One week, they consumed the carbohydrates (ciabatta bread and orange juice) first. Then they ate skinless grilled chicken, a small salad and buttered steamed broccoli 15 minutes later. The participants ate the same meal a week later, but the order of the foods was reversed, with the salad and broccoli first, and then the chicken, then the carbs. The researchers also took blood samples before the meals and 30, 60, and 120 minutes afterward. When the participants ate vegetables and proteins first, their blood sugar levels were about 29 percent lower 30 minutes after starting the meal, compared to when they ate the carbs first. At 60 and 120 minutes after participants began eating, blood sugar levels were 37 percent and 17 percent lower, respectively, compared to when the carbs came first.
What’s interesting is that the researchers found that when carbs were eaten last, the post-meal glucose and insulin levels were much lower compared to when the subjects ate carbs first during the meal. Insulin was also significantly lower when protein and vegetables were eaten first. The magnitude of the effect of food order on glucose levels is comparable to that observed with pharmacological agents that preferentially target postprandial glucose. Moreover, the reduced insulin excursions observed in this experimental setting suggest that this meal pattern may improve insulin sensitivity. Although this study was performed in diabetics, it makes sense that protein and vegetables eaten first would slow down the rise in post-meal glucose and insulin responses.
Food Order Has a Significant Impact on Postprandial Glucose and Insulin Levels, Alpana P. Shukla, Radu G. Iliescu, Catherine E. Thomas and Louis J. Aronne, Diabetes Care, doi: 10.2337/dc15-0429, published 23 June 2015.