It’s a common misconception that eating at night causes weight gain vs eating during the normal daytime hours. When it comes to weight loss OR weight gain, it truly comes down to the foods you are eating, not the time of day.
Typically, at the later hours of the night when you want a midnight snack, you don't opt for the veggies and hummus. It is true that people tend to eat higher processed foods such as candy, ice cream, or chips as late night snacking options while watching TV or movies. Yes these foods tend to pack in more bang for their buck when it comes to calories and fat, so when you are in a calorie surplus, choosing these foods as night time snacks, and mindlessly consuming the whole bag, you can see weight gain. That being said, it is not to be blamed on the slowing of your metabolism at night.
I’ve even heard claims go so far as if you eat at night, all of the food in your stomach will sit there and turn into fat.
Many diet programs will tell you a certain time to stop eating. Especially if you're an intermittent faster. But trust me all of my late night eaters, no need to stress!!
Our metabolism is a complex process and does not follow any of the time rules that diets put on them. I completely understand why people believe the concept it makes sense that our body's metabolism slows down at night time because we are less active and therefore eating at night causes weight gain. I totally see why this sounds believable! But let me break things down a little bit more for you to hopefully understand otherwise.
While yes, it is true that our metabolism slows while we are sedentary and sound asleep in bed, it is also true that our metabolism never stops working and the calories you consume in the middle of the day are absolutely no different than the calories consumed at 8pm. Eating at night does not change the process your body takes to break down the food you eat, and it definitely does not store all calories eaten at night as fat.
A research study conducted by Oregon Health & Science University debunked this myth in 2006. They completed a one-year research study using rhesus monkeys (which apparently are considered excellent models to study primates and obesity issues) and placed them all on a diet similar in composition to a typical human in the United States. The researchers were specifically looking at the monkeys' weight gain, how much they ate, and when they ate. The monkeys who ate most of their food at night were no more likely to gain weight than the monkeys who rarely ate at night. The study suggests that calories will contribute to weight gain (again, if you are in a calorie surplus) no matter what time of day when you eat them.
While there have been some other research studies to show otherwise, if you do a few searches for credible research on this topic, the end conclusion comes out to be that there is still not enough strong evidence to prove that you need to change your eating habits to eating earlier in the day and turning off your eating at 7pm to prevent weight gain.
There are also some health conditions in which night time snacking is completely appropriate and actually can be beneficial such as for people with Diabetes Mellitus. I often will encourage my diabetes patients to consume evening snacks to promote improved blood glucose readings.
Long story short, if you’re the type of person that starves themselves in the evening thinking that you shouldn’t be eating so you will prevent gaining weight, please just eat!!! If you're the person who doesn't get around to eating dinner until 8pm, this is totally fine too! You know your body and when you are hungry, so all in all learn to listen to the signals your body tells you and don't be afraid to eat later in the evening!
If you're really looking to nerd-out and take a look at a few of the articles I looked into on this topic, here are some of the sources:
Oregon Health & Science University. "Scientists Dispel Late-Night Eating/Weight Gain Myth." ScienceDaily. ScienceDaily, 2 February 2006. <www.sciencedaily.com/releases/2006/02/060202080832.htm>.
Kinsey AW, Ormsbee MJ. The health impact of nighttime eating: old and new perspectives. Nutrients. 2015;7(4):2648–2662. Published 2015 Apr 9. doi:10.3390/nu7042648