Will Eating Late Make You Gain Weight?



If you’re trying to lose weight, there’s a fair chance you’ve asked yourself the question, “Will eating late make me gain weight?”

In many ways, this would seem a logical question to ask, since there is the pervasive idea that everyone’s metabolism slows down at night to coincide with their circadian rhythm, that being the phenomenon of an organism reacting in particular ways to light and darkness, both physically and psychologically.

The prevailing idea is that we, as humans, are meant to rise with the sun, be active when it is up and eat to fuel this activity, and, when the sun goes down, settle down and go to bed.

Now, there’s no denying that our circadian rhythm does affect our overall health in a fundamental way, as a species, because circadian rhythm seems to have an affect on all life on earth.

In addition, for most of human history, we’ve followed the sun’s patterns in terms of how we’ve set our internals clocks, either by choice or design, or both.

Still, whether circadian rhythm is the main determinant in how late night eating might affect your weight is, in our opinion, questionable.

The purpose of this article is to explore the relationship between eating late and weight gain, and to shed some light on this rather complicated subject, because it is indeed not as straightforward as one might think.

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Use the following table of contents to navigate this article:

  • [ps2id url=’#1′ offset=” class=”]What Does MIT Say?[/ps2id]
  • [ps2id url=’#2′ offset=” class=”]What Does Dr. Phoenyx Say?[/ps2id]
  • [ps2id url=’#3′ offset=” class=”]Calories In / Calories Out[/ps2id]
  • [ps2id url=’#4′ offset=” class=”]Two Ladies[/ps2id]
  • [ps2id url=’#5′ offset=” class=”]What is Basal Metabolic Rate? (with Dr. Liz Lane)[/ps2id]
  • [ps2id url=’#6′ offset=” class=”]What Does Ari Whitten Say?[/ps2id]
  • [ps2id url=’#7′ offset=” class=”]Hypothyroidism and Resting Metabolic Rate[/ps2id]
  • [ps2id url=’#8′ offset=” class=”]Non-Exercise Activity Thermogenesis[/ps2id]
  • [ps2id url=’#9′ offset=” class=”]Circadian Rhythm and the Suprachiasmatic Nucleus[/ps2id]
  • [ps2id url=’#10′ offset=” class=”]Studies Have Shown…[/ps2id]
  • [ps2id url=’#11′ offset=” class=”]What Does This Girl Audra Say?[/ps2id]
  • [ps2id url=’#12′ offset=” class=”]Starvation Diet and Weight Gain[/ps2id]
  • [ps2id url=’#13′ offset=” class=”]Skinny Mukbangers[/ps2id]
  • [ps2id url=’#14′ offset=” class=”]Why is it so Easy to be Thin in Japan?[/ps2id]
  • [ps2id url=’#15′ offset=” class=”]109-Year-Old Man Ate Iced Cream Daily, Probably Didn’t Own Calorie Counter[/ps2id]
  • [ps2id url=’#16′ offset=” class=”]Nocturnal Living[/ps2id]
  • [ps2id url=’#17′ offset=” class=”]Examining Chronotypes[/ps2id]
  • [ps2id url=’#18′ offset=” class=”]Gut Bacteria and Weight Loss[/ps2id]
  • [ps2id url=’#19′ offset=” class=”]One Last Thing…[/ps2id]
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Let’s begin.

What Does MIT Say?

Let’s start with this quick paper published by MIT Medical about late night eating.


Click the link above if you’d like to peruse the paper, as it’s a handy fact sheet complete with myth-busting of the concept that late night eating necessarily will lead to weight gain.  Bookmark it if you wish.

This paper seems to have been written with students in mind, to help them form healthy late night eating habits, and to avoid things like the so-called “Freshman 15“.

That said, this information in this paper can easily can apply to anyone who is a late night snacker.

The key takeaways of this paper, we feel, are:

-The body burns calories 24/7 regardless of time, so it’s more about what you eat than when you eat.

-Part of the reason late night eating causes weight gain is because, in general, people tend to snack irresponsibly at night, partly because there’s less healthy food options.

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-We make worse eating decisions when we’re tired, as we would be more fatigued at night if we are fighting our circadian rhythm.

-Tip: Eat something with protein late at night (ie. lean turkey breast) to satiate yourself and to stave off cravings for sugar and starch.

-Specifically, late night eating is often conflated with late night snacking, and these snacks are often presumed to be unhealthy and IN ADDITION to what you’ve already eaten that day. This would make the calories contained in, let’s call it “typical” late night eating options, an overall excess to what your metabolism can handle for the day.

In other words, MIT seems to not be blaming late night eating for weight gain per se, but rather it is pointing out some of the tendencies displayed by many late night eaters, and why it may indeed lead to weight gain if we’re not careful.

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We’ve delved into some other areas to get a more comprehensive look at this subject, as reading one 3-page document isn’t enough for us to really be satisfied with this problem, regardless of who wrote it.

What Does Dr. Phoenyx Say?

Dr. Phoenyx is an M.D. and best-selling author who also happens to love vlogging, keeping it focused mainly on nutrition, fitness, and beauty.  She’s a sensible lady and has a great video here on the topic at hand…

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What she says seems sensible enough, doesn’t it?

Calories In / Calories Out

The first thing to mention about this video that needs to be emphasized is the equation of calories in / calories out.

What is calories in / calories out?


Well, this is where we already run into a bit of a pickle.

Why?  Because calories in / calories out essentially contends that a calorie is a calorie is a calorie, with the idea being that it doesn’t matter what supplies the intake of calories (healthy vs unhealthy foods) or what time that calorie is taken in (early or late at night).  It’s a very black and white viewpoint, basically.

This makes ‘calories in / calories out’ an appealing concept, because it is so simple, but its simplicity is also what makes some health experts distrust it.

FYI, the specific definition of a calorie is: the energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules).

So what is Dr. Phoenyx’s take on calories in / calories out?

She seems to take it at face value, as it does seem rather logical, whereas Kris Gunnars over at Healthline seems to think that “calories in / calories out”, is not as simple as it seems.

There are, in fact, a number of health experts who dispute ‘calories in / calories out’, labelling it as outright wrong, or, at the very least, misleading.

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But let’s assume for now that calories in / calories out makes some sense for the sake of the following analogy…

Two Ladies

What Dr. Phoenyx says in her analogy about the two ladies seems to make sense, and it’s also based on observed behaviour and results which Dr. Phoenyx has seen personally.

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One lady tries to limit her eating by eating only up until the supper hour, and not anything after that.

She does this because she thinks that eating once it gets dark (going back to the circadian rhythm idea), her metabolism will slow down and she’ll gain weight.

But, even though she stops eating at around 6pm, her eating habits aren’t great, and she consumes a fair amount of junk food, snacks, and larger portions overall.

Lady #1 thinks that because she’s doing a sort of time-restricted eating routine, and that this will save her from gaining weight.  In favour of time restricted eating, she basically ignores ‘calories in / calories out’.

Lady #2 in Dr. Phoenyx’s analogy eats during the day, and also at night, after sunset, up to 10pm, ignoring the idea that circadian rhythm dictates metabolic speed.  It is even suggested she goes to bed shortly after eating something. (GASP!)

Now, while Lady #1 eats a lot of food (both good and bad calories) and exceeds her daily intake of calories by cramming it into a window of time that abides by her circadian rhythm (sunrise to sunset), Lady #2 is more careful with what she eats, and counts her calories, even though she’s consuming some of them later and closer to bedtime.

So, Lady #2, who eats later into the night but generally healthier, should, according to Dr. Phoenyx, not gain as much weight as Lady #1, who stops eating by sunset, but consumes more calories overall than Lady #2.

Dr. Phoenyx also mentions yet another lady (Lady #3!) she knows who eats a certain type of “healthy” granola bar, which pack 400 calories each, and she on average eats about 4 or 5 of these lovelies per day – adding up to an extra 2000 calories just in granola bars that she always assumed were a good way to avoid larger meals.

It’s worth noting, at this point, that there are plenty of “snack” bars out there that people think are healthy because they provide “energy”, or contain healthy protein, but are surprisingly high in calories as well.  Read the packaging!

Main takeaways of Dr. Phoenyx’s video:

-You have to be really careful not to sneak in multiple snacks that will exceed your daily calories in, because certain tricky snacks can constitute your entire days’ caloric intake.  Once you add calories from meals on top of these snack calories, you could be eating double the calories of what you’re burning in a day!

-If you are hitting the gym, don’t just go and stand around, deluding yourself and others into thinking that you are “working hard” at the gym, when you are not working that hard, or perhaps at all.  Come up with a challenging weight and cardio routine that actually will help you to lose weight.

-You can eat late so long as you’re watching what you eat and counting calories properly.

-Diets are fads and unsustainable – so don’t bother with them.  Just eat healthy in a way that you can sustain for your whole life.

While most of this may info seem true enough to us, there are a few factors that need to be looked at closer…

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-Your personal basal or resting metabolism and its effect on the ‘calories in / calories out’ equation

-“Types” of calories.  In other words, are all calories created equal?

What is Basal Metabolic Rate (BMR)?

Watch this great video by Dr. Liz Lane of Isolator Fitness to understand what your basal or resting metabolism is, and what it means.

In this video, Dr. Lane touches on some important points that we all should consider.

She states that our calories are burned in three basic ways, with each taking up a certain percentage.  These include:

1. Thermic effects of food (digestion itself) = Approx. 10%

2. Physical activity (how much you move) = Approx. 25%

3. BMR, or how much energy you’d burn if you laid in bed all day doing nothing = Approx. 65%

This is important info to consider because a lot of people don’t know this.

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Also, it’s important to know our BMR, which we can find out roughly, using a BMR calculator such as this BMR calculator, offered by Active.com

What Does Ari Whitten Say?

Ari Whitten is a guest here on this next video by Natalie Jill, discussing weight loss, metabolism, and circadian rhythm.

FYI, Ari is an expert on the topic of energy, which he focuses on with his blog The Energy Blueprint.

Natalie Jill is a high performance coach whose motto is “Age in reverse and level up your life”.  The following discussion between them raises some very interesting points about eating late and weight gain.

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As he states in this video, Ari Whitten says that while calories in / calories out is super important, we must also take into account our basal metabolic rate when we examine our calories out, ie. how many calories we are able to burn in a day just operating our vital organs, as Dr. Lane was talking about in the previous section.

Hypothyroidism and Resting Metabolic Rate

Ari touches upon hypothyroidism, which is a disorder that can lead to things like fatigue, feeling cold, and also weight gain due to a damaged metabolism.

He says that if a person has this condition, weight loss will be less feasible, and so it’s important to know if you have this condition to begin with.

In terms of your resting metabolic rate, Ari mentions that most people don’t know much about their own resting metabolic rate, or how to influence it.

He also says that a lot of what you hear about how to influence it is not correct, so be careful whose advice you follow.

The idea of resting / basal metabolic rate also ties in with a concept called NEAT, aka Non-Exercise Activity Thermogenesis.

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This is not exactly the same as the example used in the definition we gave of BMR that Dr. Lane mentioned, ie. laying in bed all day doing nothing.  NEAT actually does include getting out of bed, but not necessary exerting yourself in the way a fitness routine would.

Non-Exercise Activity Thermogenesis

What is Non-Exercise Activity Thermogenesis?  Here’s a quote from the National Center for Biotechnology Information:

“Non-exercise activity thermogenesis (NEAT) is the energy expended for everything we do that is not sleeping, eating or sports-like exercise. It ranges from the energy expended walking to work, typing, performing yard work, undertaking agricultural tasks and fidgeting. Even trivial physical activities increase metabolic rate substantially and it is the cumulative impact of a multitude of exothermic actions that culminate in an individual’s daily NEAT. It is, therefore, not surprising that NEAT explains a vast majority of an individual’s non-resting energy needs.”

Sounds important, doesn’t it?  Yes it does!  As Ari mentions in his interview with Natalie Jill, our personal daily NEAT determines the rate at which our calories burn, just like our BMR also determines this.

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Basically, if either process isn’t optimal, we in turn burn less calories, leading to a slower resting metabolic rate and the potential to gain more weight.

Circadian Rhythm and the Suprachiasmatic Nucleus

This brings us back to the idea of following a circadian rhythm, which is an idea that Ari Whitten subscribes to wholeheartedly.

According to Ari, ignoring the natural patterns of the sun’s rise and fall can lead to weight gain, due to a confusion that occurs in the suprachiasmatic nucleus, a part of the brain that responds to the sun’s activity.

Here’s a great video explaining how the suprachiasmatic nucleus works.

And so, Ari feels that once our circadian rhythm is disrupted, this can change our behaviours around appetite suppression, and cause us to act in ways that can lead to gaining more weight, like eating poorly at a time when our metabolism is supposedly slower.

The above ideas expressed by Ari Whitten do seem to go counter what MIT stated in the beginning, not to mention Dr. Phoenyx, who have asserted the simplified principle of ‘calories in / calories out’ being the main factor to consider in trying to lose weight.

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What Ari Whitten seems to be saying is that if you are more of a nocturnal person, you are fighting natural circadian rhythms created by the sun, and sabotaging your metabolism, slowing it down.

Studies Have Shown…

One of Ari’s references to support his points was a study done on rats (Wistar rats to be precise), showing that alterations in their circadian rhythms did leave them pre-disposed to weight gain.  Read that paper by the NCBI over here.

Interestingly, another study was released by the NCBI one week later about night time eating which directly states that “Clearly, more research is required…” when it comes to night time eating and how it affects different types of men and women around the world.  Read that paper by the NCBI over here.

Whether Ari Whitten’s suggestion that following a circadian rhythm is the best way to avoid undue weight gain is true or not, we do agree with what he says towards the end of the video that humans are now limiting their exposure to natural light during the day, and exposing themselves to more unnatural light at night.

And so, now we reach a point in our exploration where we’ve looked at a few different opinions, and we can see that this is a very complex topic with no obvious answers.

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That said, we are not deterred. If you are still following along, we are going to continue this exploration of late night eating and weight gain to examine even more information, and hopefully make some breakthroughs before we’re done.

What Does This Girl Audra Say?

This Girl Audra is a certified personal trainer who has been exploring the key to weight loss for a good long while now, and in this video, she gets into the topic of why someone might be gaining weight but only consuming 1500 calories per day.

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This is where the plot really thickens, as far as weight gain goes.  Audra is talking here about how some people try to limit their caloric intake, but this only causes them to gain weight.

Starvation Dieting and Weight Gain

One woman Audra knows went down to consuming 800 calories per day and upping her cardio to a point where she was sure she would be able to lose weight.  As mentioned, some weight was lost…initially.  Then, over time, this same person began to gain weight.  How mysterious!

It is stories like these that basically turn the ‘calories in / calories out’ theory on its head, because logic would dictate that the less you consume calorically, and the more physical activity you perform, the pounds would simply melt off you at this point.

But there’s a problem here.  Which is to say that our body can adapt to situations where it feels like it’s in trouble.

If your body feels like you are starving it (which is an odd thing to think about in itself because it emphasizes how your body does things without your approval or consent), your body will hold on to things like body fat and not let go of it.

This is because body fat is, actually, the way our body stores energy for a time of crisis when we are in need of extra energy reserves.

So, if we only consume 800 calories worth of energy per day, as Audra’s friend has done, then our body will panic and try to adjust to this new eating routine, and try to hold on to every bit of fat available.  You know, just in case you might be trying to kill yourself through starvation.

What does this have to do with late night eating and weight gain, you ask?

Well, to put this in perspective, we here at Beach Baby think that if it’s possible to eat 800 calories a day, work out until you’re exhausted, and then still not lose and maybe even gain weight (?!), that’s something worth thinking about, especially once you factor in the phenomenon that eating more calories can actually raise your metabolism.

Here is yet another paper published in 2017 by the NCBI which talks about how eating less and dieting can often lead ultimately to weight gain, rather than to weight loss, as one might reasonably expect.

In the conclusion of this article, the authors do admit how complicated the whole problem of trying to lose weight is, and suggest that we need to look beyond simply reducing caloric intake to reach our goals.

To many people, results like this might be quite shocking, as it doesn’t seem to adhere to the basic logic of ‘calories in / calories out’.

Here’s yet another article, this time by Livestrong, that talks about the idea that eating more, if done correctly, can actually boost your metabolism.

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So, if you happen to stay up late, and eat long after the sun has gone down, maybe it’s better to look closer at what you’re eating, rather than when, since at this point, that seems to matter more (at least to us).

Skinny Mukbangers

Now, to throw another wrench into the works, up next we have mukbangers.

What is a mukbanger, you ask?  It’s someone who eats a ton of food on camera and interacts with their audience.

What’s interesting about mukbanging is that these people are all skinny.

Now, assuming these mukbangers aren’t purging themselves after every meal, which they may in fact be doing, how in the world can these people eat so much and not get disproportionately large in doing so?

Here’s a good quora thread to answer this question, if you want to see what others have to say about it.  Here’s another good thread on the topic.  And another over on Reddit.

Answers include:

-Hyper metabolism

-Puke after eating

-Hereditary skinny bodies

-Only doing this once in a while

Now, it wouldn’t be too much of a stretch to imagine that these mukbangers don’t exactly take their circadian rhythms into account when doing these food-eating stunts of theirs.

What we really find interesting about mukbangers is that it really brings into question how some people are able to digest food.  Not to mention competitive eaters like Matt Stonie here…

Of course, these mukbangers and hot dog eating champs obviously have their little tricks to get around eating so much food if they don’t want to gain weight, but there are probably a few of them who actually can simply eat a lot, and stay skinny.

This points to genetics, physique, and high metabolism, and surely if you’re reading this, you know someone who can eat anything they want and not get fat.  Those people do exist.  Indeed, some people have trouble gaining weight, not losing it.

However, if you are reading this, then chances are you are not one of those people who can eat several tubs of iced cream and have it not affect their outward appearance (their inward appearance may be another story).

These things are worth considering, since you may be counting calories obsessively, but these mukbangers, competitive eaters, and genetically pre-disposed thin folks probably have super high metabolism and – coincidence? – some of them eat a ton of food daily.

We leave it up to you what you want to make of people like mukbangers.

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Pre-disposition to not losing weight or being larger may even have to do with ethnicity, as Asians (many mukbangers being Asian) are less obese than North Americans, on the whole.

If you want to explore this idea more, read this paper about the correlation between race and obesity.

Why is it so Easy to be Thin in Japan?

Next, watch this interesting video showing why it can be easier to maintain a thinner physique in Japan, for instance.

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As you can see, the food choices there are often healthier in some ways than in North American diet, and more people seem to enjoy a more balanced diet with more variety.

109-Year-Old Man Ate Iced Cream Daily, Probably Didn’t Own A Calorie Counter

At this point, you might be completely confused, but then again, you might be like us and feel like you have gained at least some understanding of the nuances around what you eat, when you eat, and who you are as a unique individual.

Speaking of unique individuals, watch this video about this 109-year-old man who shares his secrets to a good life, with some interesting answers given around the topic of health you may not expect.

First of all, R.I.P. – Richard Overton died December 28th, 2018, age 110.

So, to recap what he said, he ate iced cream every day, because he liked it.  He smoked a lot of cigars, he drank a lot of coffee, drank a lot of whiskey, and would often get up at 1, 2, or 3 am.

The reason we included Richard Overton in this article is one because he lived to 110, and he also seemed to be at least partially nocturnal. His schedule seemed reasonable (at least to him), but not really adherent to sunrise and sunset, per se.

And, even though he ate iced cream every day, he was not overweight.  What can we attribute this to?  Your guess is as good as ours.

In any case, Richard made it farther in life chronologically speaking than most of us will, and he seemed pleased to have his cats, and his iced cream, and his unorthodox schedule.

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Make of him what you will, but we think that if Richard Overton can be 109 years old and stay up late and cook himself some Campbell’s soup and not stress over getting fat, maybe we can too.

Nocturnal Living

Since we are fairly far afield in this discussion, we may as well add this guy into the mix – Sacred Serpent.

“My thirst for wisdom supersedes my desire for sleep” – Sacred Serpent

Regardless of his views, we included this video here because clearly this guy is nocturnal, and clearly not overweight.  Is it because he’s not up late eating all night, and rather seeking knowledge?  Oh, probably that’s why.

In any case, he does raise some good points about those of us who like being up late to experience the quietude of night time, the stars, the moon, etc.  These are things some of us actually do prefer to the hustle and bustle of the day.

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This is not an argument for nocturnal living, as such, however it is worth considering that, once again, any problem you may have with your weight is likely related more to what you are doing being up so late, just like it matters what you are doing (and what you are eating) during the day as well.

Examining Chronotypes

And since we’re on the topic of nocturnal behaviour, you should probably watch this video which talks about chronotypes, ie. early birds vs. night owls, and what kinds of factors can lead to someone being one versus the other.

If you really want to dig deep into the topic of chronotypes, head on over here to this article by Nature.com which talks about the study of roughly 700 000 subjects, and the how it ties in circadian rhythm and potential health problems.

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The Nature.com article was fairly recent, as in 2019, and as the video above states, there was no definite correlation between being a night owl, and weight gain, a result that may surprise some people.

Gut Bacteria and Weight Loss

One factor we haven’t explored yet which may hold a missing piece of the puzzle as to unexpected weight gain involves gut bacteria.

Here is an awesome Mayo Clinic Radio video which interviews gastroenterologists Dr. Purna Kashyap and Dr. Vandana Nehra, who discuss how gut bacteria can interfere with weight loss.

This topic is certainly interesting, and certainly complicated, since very few regular people seem to know much about their own gut biochemistry.

And yet, this is the part of your body which is present in order to break down food, converting to to whatever it wants to convert it to, whether that be energy, or fat stores.

Here are two excellent papers on gut biome and its relation to obesity, once again published by NCBI.

The Gut Microbiome Profile in Obesity: A Systematic Review



The Gut Microbiome and Its Role in Obesity


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What these two papers seem to suggest is that more research is needed, however there appears to be a correlation between similar microbiota in obese individuals, suggesting that with a further understanding of this microbiota, we can perhaps customize someone’s diet to suit their own unique microbiota, or consider a transplant of some kind.

One Last Thing…

Here is one last short video which outlines, once again, that eating late and weight gain are unlikely to be related, at least according to nutrition-based website, streamingwell.com.

Now that we’ve shared with you all of this knowledge about the relationship between eating late and gaining weight, we hope you are somewhat closer to a solution, if indeed you have a problem.

Otherwise, we hope you have enjoyed this article!  Leave a comment below if you’d like to share something!

About the author: Janis is loves to study topics involving health & wellness, and is obsessed with natural supplements and learning about what goes into them and what they do, or don’t do.  She went to university for nutrition with a minor in economics. Out of the Beach Baby Squad, she is the most likely to stay home. She also does the most of the product reviews on this site.

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