Let’s face it, a large majority of college students like to eat, there’s no doubt about that. If I had to guess, I’d say it’s because of how accessible food is. We can always find an open restaurant, order anything we want online, have it delivered to our doors, and pay for it with the swipe of a card. Food is available at all hours of every day and college students take advantage of the opportunity. As we do this, we normally feel guilty afterward because on some level–whether it be conscious or subconscious–we know that this isn’t healthy, but how unhealthy is it exactly? In the long run, will eating late at night make you gain weight faster than eating during the day?
Well, as much as we want an answer to that question, there just might not be one. However, I’ll approach that in more detail later. First, I want to talk a little bit about the metabolism. According to several sources–such as this one and this one–the “body doesn’t process food differently at different times of the day” because “a calorie is a calorie, regardless of when you burn it.” When we think about this, it makes perfect sense, right? Our body is going to process food the same way, even when we’re winding down for the night because, although we’re done being active, our internal organs are still functioning which, in turn, is burning calories. This is basic high school health class knowledge, weight gain occurs depending on caloric intake and activity levels (excluding disease and genetics), and there are studies which go along with and backup this idea.
For example, one study conducted at the Oregon Health and Science University, highlighted in this Beth Israel Deaconess Medical Center article, used rhesus monkeys to test the hypothesis of eating late leading to weight gain. The results showed that the monkeys who ate later were “at no greater risk” than the monkeys who ate earlier in the day. This result is also consistent with the beliefs of the credible National Institute of Diabetes and Digestive and Kidney Disease discussed in the same article as well as the U.S. Department of Agriculture’s Weight Control Information Network which is mentioned in this article. Both of these sources support my aforementioned claim–that it’s daily and long-term eating and activity which determines weight gain, not the specific time you consume calories.
There are some studies which claim otherwise. According to Northwestern University researchers who conducted a study that was published in the journal Obesity, “eating at night led to twice as much weight gain. This result, however, was determined by one trial which observed mice (source). Meanwhile, another study published in The American Journal of Clinical Nutrition (AJCN) concluded that “nighttime eating was common, and it predicted weight gain,” but there were many factors to consider in this study which could lead to confounding variables. For example, The AJCN’s study was not randomized, it used white people and Pima Indians as well as observed them as inpatients in a research unit; not in a normal everyday environment.
So with that in mind, it is safe to say that the answer to the question “does eating late make you fat?” is inconclusive, but I may be able to provide some insight on why people think it does. You see, despite the fact that every study differed, many of them still managed to agree on one thing: the things people were eating as “midnight snacks.” In all of the sources I mentioned above, as well as this one, it was a common claim that the reason why it seemed people were gaining weight after eating later in the evening was because they were consuming high-calorie foods. People tend to not only lack self-control and intake when they eat later, but they are also more inclined to reach for quick and easy snacks, and if you didn’t know already, quick and easy snacks tend to be higher in calories. I’m sure the light bulb just went off in all of your heads like it did mine, and as much as I’d like to go into this topic more, it’s going to have to wait until next time as this is getting quite lengthy. Look out for my next post though, because I plan on giving a more thorough examination of the question: Why do we crave junk food at night? Stay tuned.