Dear FutureDerm,
I’ve recently heard that eating after a certain time, like 6:30 PM, can hurt your metabolism and make you gain weight. I’ve also heard it doesn’t make a difference. Which is true?
-Late Night Eater
Dear Late Night Eater,
The answer is technically no – most nutritionists uphold that a calorie is a calorie, regardless of whether or not it is consumed at 11 PM or 11 AM. While it is true that metabolism slows throughout the day, falling to about 40% while asleep, keep in mind metabolic rate varies from one person to another and is affected by sex, age, and amount of lean body mass (muscle). Very obese people have much faster metabolisms than very lean people (American Journal of Clinical Nutrition, 1982), so they technically burn calories faster.
However, there are some real concerns that can occur with eating at night, which include the following:
Do You Binge Eat Exclusively at Night?
If you binge eat at night and exhibit the following symptoms, you may have Night Eating Syndrome, or NES:
- Skip breakfast;
- Consume at least 25% of calories after dinner;
- Suffer from depression or anxiety, particularly including guilt after a bingeing episode;
- Have trouble sleeping at night/insomnia.
Late night binge eating is also associated with very unhealthy eating habits, such as high caloric intake, high sodium intake, and low protein intake (International Journal of Eating Disorders, 2008).
However, it is important to keep in mind that night eating syndrome is nothing of which to be ashamed. It is not always a matter of self-control and bad habits, but actually at times may be caused by a hormonal or chemical imbalance, as night eating syndrome has been correlated with low melatonin levels and high appetite-stimulating leptin levels (Eating Disorders and Obesity, 2005). While methods like maintaining day-night cues can help to regulate your melatonin levels somewhat, it is best to talk to your physician, as many of the symptoms of NES have been resolved with an antidepressant, such as sertraline (International Journal of Eating Disorders, 2004).
If you binge eat throughout the day, not just at night, you may suffer from Binge Eating Syndrome, not night eating syndrome. The good news is that Binge Eating Syndrome responds well to traditional weight reduction programs (International Journal of Obesity, 2002).
Self-control May Be Lower at Night
Self-control is like a muscle: The more you use it, the stronger it gets. Conversely, the more you let your self-control rest like a couch potato, the weaker it gets. Research has shown that self-control is weakened with repeated stimuli (Journal of Personality and Social Psychology, 1998). In the study, subjects were told to try to control their mood during an emotional movie. After, it was found their physical stamina actually decreased. In another portion of the study, it was found actively trying to suppress thoughts impaired subsequent efforts to control enjoyment.
In other words, after an entire day when your willpower has gotten you to resist everything from telling your boss how you really feel to not buying yet another pair of shoes, you and your self-control are weak.
Not Tuned into Bodily Clues at Night?
In Chronobiology in 2003, it was found night workers tend to eat more. In the study, night workers were found to significantly alter their food intake, desiring cold food over hot prepared meals, and choosing food based upon habit and time availability and less by appetite than when the same workers worked the day shift. It is possible people just are not as tuned into bodily signals, such as appetite cues, at night.
Bottom Line
Eating at night does not make much of a difference in terms of the metabolic impact on calorie consumption. However, nighttime eating does matter when things like self-control and bodily appetite cues are taken into consideration. Unless you are terribly disciplined and consistent to a fault, it may not be a bad idea to restrict your last meal to no sooner than three hours before bed.