Sleeping on a full stomach - science or woo?
September 21, 2016 7:14 AM   Subscribe

Is there any reputable evidence that going to bed on a full stomach is bad for you, healthwise?

This cropped up in an online discussion where several posters made the assertion that it was bad for you, health and weight wise. The main cite for this appeared to be a study which suggested that those who ate before 5pm only lost weight faster. I've been googling but, as with anything to do with healthy eating, there is a fair amount of misinformation and woo kicking around.
posted by threetwentytwo to Science & Nature (10 answers total) 3 users marked this as a favorite
So i asked a broader version of this question awhile back and was pointed at some good resources.

I will say in my investigations since there is vanishingly little real science behind most dietary assertions. I did look at the evening eating thing to see if there had been real impact studies as opposed to common sense assertions and I wasn't able to find them. I did find a meta-study that pointed to a lot of correlation but not causation. I'll see if I can find that for you.
posted by French Fry at 7:33 AM on September 21, 2016 [3 favorites]

I would want to know more about that study-- does it account for the fact that a lot of people binge on desserts/snacks after dinner so it's not really the time of day, but the fact that they maybe cut out post-dinner snacking?
posted by kapers at 7:46 AM on September 21, 2016

The best evidence I've seen so far was a National Geographic article, a million years ago, about sumo wrestlers in Japan. To gain weight, they would overeat right before going to bed. Since they didn't burn off those extra calories (even being awake and moving around burns a few), they put on the pounds.

That's about it.
posted by Melismata at 7:48 AM on September 21, 2016 [1 favorite]

Hmm, found this quick summary of some stuff from Prevention. Here is some research from the quoted researcher that may be of interest. Don't know (because it wasn't linked to, hate that), but this may be another of the studies mentioned.
posted by cotton dress sock at 8:08 AM on September 21, 2016

"Circadian Timing of Food Intake Contributes to Weight Gain" (freely accessible research article, using mouse model, published in Obesity).

"The night-eating syndrome and obesity" (freely accessible review article, covers many other investigations, published in Obesity

"Timing of food intake predicts weight loss effectiveness" (paywalled Nature article, might be able to scrounge a copy with some digging)

"Nighttime eating: commonly observed and related to weight gain in an inpatient food intake study" (Freely accessible, human study, notes correlations between time of eating and weight gain)

"Night eating syndrome and nocturnal snacking: association with obesity, binge eating and psychological distress" (accessible article, human study of bariatric surgery candidates, International Journal of Obesity)

TLDR: In addition to the lore of Sumo, it makes intuitive sense to think that eating food before bed can cause weight gain. Food eaten during the day fuels daytime activity. Calories ingested just prior to sleep have no direct demand, so get stored.

It is of course far more complicated, and we are still figuring out the details, in particular the biomechanics of circadian rhythms and their influence on metabolic regulation networks. But hopefully the research above will convince you this is not just hearsay and lore, it is hearsay and lore that happens to be generally supported by a wide array of relatively recent peer-reviewed studies. Many more such studies can be found by looking at forward and reverse citations of the above, and using google scholar to search keywords from these studies.
posted by SaltySalticid at 8:22 AM on September 21, 2016 [4 favorites]

I don't know about the weight gain part, but it's definitely bad for acid reflux.
posted by thetortoise at 8:28 AM on September 21, 2016 [13 favorites]

I don't know if you'd consider this "reputable evidence", but my personal experience has been that eating right before bed leads to stomach upset, since the digestive process slows down and the food just "sits".
posted by WCityMike at 8:36 AM on September 21, 2016

So the problem I have with many of the studies mentioned is that they rely on survey self reporting, animal tests, specific conditions like NES or Nocturnal Hyperphagia or very select populations. Those that are more clinically controlled are again drawing correlations and often don't account for many important variables.

The best study linked here is the one that focuses on Pima Indians in Arizona as it actually put people in a clinical unit. But in that study people could eat whatever they wanted after 3 control days and the folks who ate at night ate much worse food during that time, so the hour of eating can't be said to be a discrete variable.

I'm not disputing that eating late is a bad idea for all manner of common sense and anecdotal reasons. Not the least of which is when I'm tired I make stupid decisions. But color me highly skeptical of most assertions of "this thing basically makes sense, let's report it on the news as a science fact"
posted by French Fry at 9:45 AM on September 21, 2016 [3 favorites]

A few other relevant and freely accessible research articles for anyone interested in the topic as discussed in the scientific literature, rather than fora and newpapers:

"Timing of food intake and obesity: A novel association"

"Meal frequency and timing in health and disease"

"Nutrients, Clock Genes, and Chrononutrition"

"Chronobiology and Obesity: Interactions between Circadian Rhythms and Energy Regulation"
posted by SaltySalticid at 10:12 AM on September 21, 2016 [1 favorite]

It may be less of a question of eating at night as opposed to non-time-restricted eating: Time-Restricted Eating without Reducing Caloric Intake Prevents Metabolic Diseases in Mice Fed a High-Fat Diet. So the problem might be not that you're eating at night, rather that you're eating all day. If you ate your first meal at noon, then eating at ten p.m. might be fine.

To me, this makes more sense than the "calories just get stored when you sleep right after!" model, which seems like a just-so story.
posted by praemunire at 10:59 AM on September 21, 2016 [2 favorites]

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