You’ve heard before that breakfast is the most important meal of the day…it gives you energy for the day and provides nutrients your body needs after the overnight fast. Still, about 20% of Americans find a reason to skip breakfast—despite the fact that doing so is known to make people overeat later in the day and gain unwanted weight.

Now, new research reveals yet another very important reason not to skip breakfast—it can mess with your metabolic function…and may even increase your risk for diabetes.


The new study involved overweight or obese women who did not have diabetes. (But even if you are not overweight or you are a man, there is important info here for you.) Most of the participants usually did eat breakfast—but the researchers wanted to compare what would happen on days when the participants had a morning meal versus days when they skipped it. Although many studies rely on participants’ recollections of what they ate, such recollections often are inaccurate—so for this study, the researchers provided the meals and knew exactly what was eaten.

After eating standardized dinners the night before, participants visited the lab early in the morning on two separate days about a month apart. They were randomly assigned to either have breakfast or not have breakfast on their first visit…and to do the opposite on their second visit. On the breakfast morning, participants were given a meal consisting of wheat flakes with milk, scrambled eggs and orange juice, which contained 25% of their daily calorie intake and a healthy balance of protein, carbohydrate and fat…on the no-breakfast morning, they just drank water. Then four hours later, everyone in the study—whether they had been given breakfast that day or not—received a lunch that contained 35% of their daily calorie intake.

Starting just before lunch, blood was drawn every half hour for three hours so that the participants’ blood levels of insulin and glucose could be measured. (Normally, blood glucose rises after a meal…the pancreas senses the rising glucose and releases insulin…and then the insulin draws the glucose into the body’s cells so it can be used for energy.)

Metabolic mayhem: Those postlunch blood tests revealed some disturbing results! Compared with the days on which participants ate breakfast, on the no-breakfast days, they produced up to 39% more insulin, yet higher levels of glucose remained in their blood after lunch. Both of these signs point to insulin resistance, a condition in which the body’s cells do not respond to insulin as efficiently as they should—meaning that more insulin is required to do the job, yet glucose levels remain abnormally high.

Now, the insulin resistance seen in this study was temporary—but it occurred after the participants skipped breakfast just one time. The concern is that habitually skipping breakfast might lead to chronic insulin resistance, which is a major risk factor for type 2 diabetes.

Why might the effects of skipping breakfast be worse than those of skipping the midday or evening meal? No one knows for sure…but it might have something to do with the elevated levels of free fatty acids that occur after a prolonged fast, which can lead to insulin resistance, the researchers said.

Start your morning right: To keep your blood glucose and insulin levels on an even keel, researchers suggested eating a nutritionally balanced breakfast within two hours of waking up, aiming to consume between 20% and 35% of your total day’s calories.