Researchers kept 23 volunteers up all night and then scanned their brains as they viewed pictures of food. Two key regions in the brain showed significant changes in activity.
The amygdala is believed to play an important role, not so much in hunger as appetite. The two may sound the same but they’re not. Hunger is your body’s response to the need to refuel. A grumbling stomach, light headedness or fatigue may be accompanied by hunger.
Appetite can be stimulated even in the midst of a completely fed state. You’ve perhaps seen this when you’re so full you could burst, yet you “make room” for grandma’s apple pie. With or without hunger, our appetites can be stimulated by the smell of food, boredom, emotions, cravings, you know the deal. The amygdala is also associated with emotions, so it’s notable that its activity is linked with appetite rather than hunger. (3)
In this study, sleeplessness caused excessive activity in the amygdala as the 23 looked at food photos. With this much stimulation in the craving center of our brain, our power to resist weight-gaining foods is largely reduced. Researchers looked on with confirmed suspicions as doughnuts, potato chips and double bacon cheese burgers snagged participants’ hungry eyes and excited their amygdala.
Frontal Cortex and Insular Cortex
The frontal cortex, or frontal lobe, is involved with judgment, choice and decision making. It’s the part of our brain that enables us to foresee consequences of our actions, choose between right and wrong or good and bad, learn and establish socially acceptable behavior, and remember the emotions associated with certain experiences, such as fried twinkie bad, fresh avocado good. (4)
The insular cortex is located behind the frontal, folded deep within the brain and separating the the frontal from the larger lateral section (lateral sulcus aka lateral fissure). Scientists hold that this piece of our brain puzzle plays a role in emotions, motor control, self-awareness, overall cognition, interpersonal experience and homeostasis. (5) If this section is healthy and functional, we should have more control over what we reach for, maintain balance, think clearly, and be able to make conscious choices outside of raw physical cravings.
As the sleepy showed increased activity in their appetite center, they showed significantly less stimulation in these two decision-making areas of the brain. One might consider that these areas represent our self-control centers. And this study shows they all but shut down after pulling an all-nighter.
Other studies have shown that lack of sleep so greatly reduces insulin sensitivity that we become chemically similar to Type II Diabetics. Insulin resistance causes blood sugar levels to peak, activating fat storage, and then valley, causing a high and then a crash. One study found that sleep deprivation over the course of only two nights caused an 18% reduction in leptin (signals satiety) and a 28% increase in ghrelin (the hunger signal). (6)(7) This equals hunger a diminished capacity to feel full.
All things considered, it’s looking like sleeplessness deprives our bodies of necessary rejuvenation and replenishment, causing our bodies to scream out for cheap sources of energy. It’s not the best solution, but if you won’t give it sleep, the body will take the quickest source of energy available. This would be sugar and quickly assimilated refined carbohydrates, the very ones that translate quickly to the accumulation of fat.
What’s the moral of this story? Respect your body’s need for sleep. And if you miss a night, try your best to resort to restorative slow breathing techniques, relaxation poses, quiet meditation, or naps to help prevent binging on the wrong foods.
Above all, remember that your sleep tonight is the result of your lifestyle habits in the days and weeks prior. Even the consistent loss of one hour can upset your health and balance. Make deep sleep a priority in your life. Keep the room dark, quiet and cool. Discover whether you personally need 7, 8 or 9 hours each night to awaken fully refreshed. Plan ahead so that you get the full 7-9 hours of sleep you need. Taking care of your body this way could change your life.