Saturday , November 25 2017
Home / Conditions / Type 2 Diabetes / Fasting Until Noon Increases Postprandial Glucose Levels, Impaired Insulin Response After Lunch and Dinner

Fasting Until Noon Increases Postprandial Glucose Levels, Impaired Insulin Response After Lunch and Dinner

Breakfast consumption led to a reverse metabolic state in individuals with type 2 diabetes

In type 2 diabetes (T2DM), controlling postprandial glycemic levels has always been an important factor in managing diabetes treatments. Having breakfast daily has demonstrated to be important for the 24-hour regulation of blood glucose. This is currently an important factor due to an increasing number of people skipping breakfast. Skipping breakfast has been shown to increase HbA1C and all-day postprandial hyperglycemia (PPHG) in patients with T2DM. In contrast, consuming a high-energy breakfast and a low-energy dinner reduce all-day postprandial glycemia. Daniela Jakubowicz and colleagues hypothesized that breakfast omission will increase PPHG after both lunch and dinner and can lead to impaired insulin response in T2DM.

This was a randomized, open-label, cross-over-within-subject clinical trial, which included 26 individuals with T2DM; however, only 22 participants completed the trial. There were 10 participants who were being treated with just diet alone and 12 participants were treated with diet and metformin. On the meal test days, glucose and insulin levels were not statistically different between these individuals, whether they were on metformin or not.

Participants underwent two separate all-day meal tests with a washout period of 2 to 4 weeks between test days. These individuals were given identical lunch and dinner that had the same macronutrient content and composition whether they were in the breakfast group (YesB) or in the group with no breakfast (NoB). Those who were in the YesB get their first meal, which is their breakfast, at 0800h; whereas those that were in the NoB group get their first meal, which is their lunch, at 1330h.

Results showed that skipping breakfast led to higher glycemic index response and high levels of glucagon and FFA and reduced levels of insulin, C-peptide, and iGLP-1 after lunch and dinner, whereas breakfast consumption led to a reverse metabolic state. Breakfast omission resulted in impaired insulin secretion after lunch and dinner, which can be seen by the delayed peak insulin and reduced concentrations of plasma insulin and C-peptide, according to the study. iGLP-1 level was also lower when breakfast was skipped. Therefore, skipping breakfast worsened the postprandial glucose level and impaired insulin secretion. The researchers speculated that this is due to incretin regulation in the body because “β-cell memory and sensitivity to glucose are both enhanced by GLP-1”; therefore, on the YesB day, the higher levels of GLP-1 “may explain both the enhanced insulin secretion and the reduced glycemic response after lunch and dinner.”

They also postulated that the effect of the circadian clock on glucose homeostasis might play an important role in this phenomenon. Skipping breakfast disrupts the normal meal schedule and prolonged fasting period, which may worsen postprandial glycemic level throughout the day.

Therefore, Jakubowicz and colleagues concluded that extended fasting period by skipping breakfast lead to reduced insulin and GLP-1 level, which decreases the activation of β-cells. This mechanism along with disruption of the circadian clock lead to increased PPHG after lunch and dinner in T2DM. These findings emphasize the importance of having breakfast in the morning to prevent postprandial glucose excursions and complications in T2DM.

Practice Pearls:

  • Breakfast omission resulted in impaired insulin secretion after lunch and dinner.
  • Having breakfast results in higher level of GLP-1 and will enhance insulin secretion and reduce glucose level after lunch and dinner.
  • Having breakfast in the morning prevents postprandial glucose excursions and complications in T2DM.

Jakubowicz D, Wainstein J, Ahren B, Landau Z, Bar-Dayan Y, and Froy O. Fasting Until Noon Triggers Increased Postpranial Hyperglycemia and Impaired Insulin Response After Lunch and Dinner in Individuals With Type 2 Diabetes: A Randomized Clinical Trial. Diabetes Care 2015;38:1820-1826. Web. 29 Sep 2015.