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What does it mean when you crave food in the middle of the night? I can eat nutritiously all day, but come one, two, three in the morning, I am starving to death and I have to EAT. I bring fruit, crackers and a vegetable/fruit smoothie up every night or I'll be up and down the stairs all through the night.
I exercise at least five days a week and for the most part maintain a healthy diet. Any thoughts or suggestions?
-- Allison
Allison is hardly alone in her late-night eating habit. We talked to nutritionists and sleep experts to get a better sense of what causes us to break into the fridge in the wee hours. Turns out, there are many conditions that can cause this type of eating, but they have markedly different symptoms.
"It could be something called night eating syndrome, which is also associated with lack of appetite in early morning," says Joseph Kaplan, director of the Mayo Sleep Center at the Mayo Clinic in Jacksonville, Fla. "It happens when the body's clock is on one schedule for being awake and sleep and different schedule for when they get hungry."
No one knows what causes the condition, but those who have it do have some commonalities: it's more prevalent in obese patients, those with anxiety and depression and, according to Kaplan, higher leptin levels among obese night eaters. Leptin is the hormone secreted by fat cells that signals to the brain that the body has reached satiety.
There's more evidence that night eating syndrome may be centered in neural hormonal cycles: extreme cases of night eating symptom have been successfully treated with the SSRI Zoloft, which affects the area of the brain that controls the sleep-wake and eating cycles, Kaplan explained.
Night eating syndrome is dangerous because it leads to weight gain and because it is disruptive to the sleep cycle. If someone is waking up in the middle of the night, they can't properly move through their sleep cycles, what Kaplan terms "sleep architecture": three stages of non-REM and REM sleep that are necessary to be properly rested.
Anyone concerned about night eating syndrome should speak to a doctor, Kaplan counsels, where diminishing potential stressors and sources of anxiety should be the first areas of inquiry. "Look carefully at stressors, anxiety, depression -- talk to a doctor about those possibilities," says Kaplan. "See a dietician to control calories. And if it's still a problem, drug therapy can be considered. Also, Bright light therapy has worked in a few cases."
The relationship to anxiety could be a lot similar, says Dr. Loren Greene, a clinical associate professor in the Endocrinology Division of the Department of Medicine at NYU. "You're anxious, so you don't sleep well and then it's comforting to eat something."
But Greene suspected something else at play: reactive hypoglycemia. While a healthy person will emit insulin and experience blood sugar changes immediately following a meal as a reaction to the glucose they ate, those who are pre-diabetic may have a delayed insulin secretion, causing a disruption in sleep.
"If you eat a late dinner, say 10 p.m. with a dessert, some times you start putting out insulin in the middle of the night which can cause your blood sugar to peak and drop," Greene says. She recommended that, as a diagnostic measure, nighttime eaters should ask their doctors for a blood sugar test kit. When they wake up, they can prick a finger and see their blood sugar level. If it's low, they can assess why: while it could be a combination of pre-diabetes and late eating, it could also be one of the several medications that cause low blood sugar.
There are several other conditions that can be associated with nocturnal eating. Greene pointed to a case study of a night eater who had a tumor that affected her pituitary center -- the brain region related to feelings of satiety, but stressed that this was highly unusual. Binge eaters may also pick late night for their extra meals.
Given the healthy lifestyle Allison described and the lack of details about stressors, BMI and more, the best solution, agreed both doctors was to go to her general practitioner armed with as many observations about the night eating habits as possible.
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