Meal Frequency and Energy Balance

Introduction
I read a tremendous number of research papers each week in order to keep up with the rapidly changing field of nutrition, physiology, and all topics related to body recomposition. From time to time, I like to review research papers that I think are interesting to my readers; while these are usually new papers, sometimes, I also go back to older papers that happen to be relevant or important. This week’s paper is one of those older papers that addresses one of the longer-standing myths in the field of weight loss, that of meal frequency.

Title
Bellisle F et. al. Meal frequency and energy balance. Br J Nutr. (1997) 77 (Suppl 1):S57-70.

Abstract
Several epidemiological studies have observed an inverse relationship between people’s habitual frequency of eating and body weight, leading to the suggestion that a ‘nibbling’ meal pattern may help in the avoidance of obesity. A review of all pertinent studies shows that, although many fail to find any significant relationship, the relationship is consistently inverse in those that do observe a relationship.

However, this finding is highly vulnerable to the probable confounding effects of post hoc changes in dietary patterns as a consequence of weight gain and to dietary under-reporting which undoubtedly invalidates some of the studies

We conclude that the epidemiological evidence is at best very weak, and almost certainly represents an artefact. A detailed review of the possible mechanistic explanations for a metabolic advantage of nibbling meal patterns failed to reveal significant benefits in respect of energy expenditure.

Although some short-term studies suggest that the thermic effect of feeding is higher when an isoenergetic test load is divided into multiple small meals, other studies refute this, and most are neutral. More importantly, studies using whole-body calorimetry and doubly-labelled water to assess total 24 h energy expenditure find no difference between nibbling and gorging. Finally, with the exception of a single study, there is no evidence that weight loss on hypoenergetic regimens is altered by meal frequency. We conclude that any effects of meal pattern on the regulation of body weight are likely to be mediated through effects on the food intake side of the energy balance equation.

 

My comments
Perhaps one of the longest standing dogmas in the weight loss and bodybuilding world is the absolute necessity of eating frequently for various reasons. Specific to weight loss, how many times have you heard something along the lines of “Eating 6 times per day stokes the metabolic fire.” or “You must eat 6 times per day to lose fat effectively.” or “Skipping even one meal per day will slow your metabolic rate and you’ll hoard fat.” Probably a lot

Well, guess what. The idea is primarily based on awful observational studies and direct research (where meal frequency is varied within the context of an identical number of calories under controlled conditions) says that it’s all basically nonsense. The basic premise came, essentially out of a misunderstanding of the thermic effect of food (TEF) also called dietary induced thermogenesis (DIT) which are the calories burned in processing of the food you eat.

While TEF differs for the different nutrients, on average it constitutes about 10% of a typical mixed diet (this varies between nutrients and slight differences may be seen with extreme variations in macronutrient intake). So every time you eat, your metabolic rate goes up a little bit due to TEF

Aha! Eat more frequently and metabolic rate goes up more, right? Because you’re stimulating TEF more often. Well, no. Here’s why:

Say we have two people, both eating the same 3000 calories per day from identical macronutrients. One eats 6 meals of 500 calories/meal while the other eats 3 meals of 1000 calories/meal and we’ll assume a TEF of 10%. So the first will have a TEF of 50 calories (10% of 500) 6 times/day. The second will have a TEF of 100 calories (10% of 1000 calories) 3 times/day. Well, 6X50 = 300 calories/day and 3X100 = 300 calories/day. There’s no difference.

Of course, if you increase food intake from, say, 1500 calories to 2000 calories, you will burn more with TEF; but this has nothing to do with meal frequency per se, it has to do with eating more food. I only bring this up because I’ve seen people (try to) argue the positive effect of TEF by dredging up studies where folks ate more total calories. Of course TEF goes up, but not because they are eating more frequently; rather it’s because they are eating more food in total.

I want to address that last bit a little bit more since the fact that TEF goes up with increasing food intake is often used to argue that “metabolism chases intake” and to make arguments for eating more to get lean. Here’s the problem with this ‘logic’. Assuming an average 10% TEF, increasing food intake from 1500 calories to 2000 calories per day will increase caloric expenditure by 50 calories. But you had to eat 500 more calories to get it. So even if you burn 50 calories more, you’re still consuming 450 more calories than you would have otherwise. Basically, the logic is akin to saying “I saved $100 by spending $1000 because what I bought was 10% off”. Right, but you’re still out $900 that you wouldn’t have spent and you’d have saved $1000 if you hadn’t bought it in the first place. The same logic applies here.

Which brings me, the long way around, to the above review paper which examined not only earlier observational work but also direct studies of varying meal frequency on either weight loss (during such studies) or metabolic rate. And, with the exception of a poorly done study on boxers (which I’ll discuss a bit below), they found no effect of varying meal frequency on any of the examined parameters. No increase in metabolic rate, no increase in weight loss, no nothing. What’s going on?

They concluded that earlier studies finding an effect of meal frequency on weight gain (or loss) had more to do with changes in appetite or food intake, not from a direct impact on metabolic rate. For example, early observational studies found that people who skipped breakfast were heavier and this still resonates today with the idea that skipping breakfast makes you fatter. However, the review points out that this may be confusing cause and effect: people often start skipping meals to lose weight.

I’d note, tangentially and I’ll come back to this below, that there is no data in humans that skipping a single meal or even a day’s worth of meals does anything to metabolic rate. Human metabolism simply doesn’t operate that quickly and various research into both fasting and intermittent fasting show, if anything, a slight (~5% or so) increase in metabolic rate during the initial period of fasting. The idea that skipping breakfast or a single meal slows metabolic rate or induces a starvation response is simply nonsensical.

Basically, there are a lot of confounding issues when you start looking at observational work on diet and body weight. As I discussed in detail in Is A Calorie A Calorie, you often find that certain eating patterns impact on caloric intake. And it’s those changes in caloric intake (rather than the eating patterns themselves) that are causing changes in weight

For example, some early studies actually found that eating more frequently caused weight gain, mainly because the foods being added were snacks and were in addition to normal food intake. In that situation, a higher meal frequency led to greater food intake and weight gain. But it wasn’t the meal frequency per se that caused the weight gain, it was the fact that folks were eating more.

Other studies have shown that splitting one’s daily calories into multiple smaller meals helps to control hunger: people tend to eat less when they split their meals and eat more frequently. But, again, this isn’t an issue of meal frequency per se, it’s because food intake is decreased. When folks eat less, they lose weight and IF a higher meal frequency facilitates that, it will cause weight loss. But, at the risk of being repetitive, it’s not because of effects on metabolic rate or any such thing; it’s because folks ate less and eating less causes weight loss.

I’d note that the above observation isn’t universal and some people report that the simple act of eating makes them hungrier. Many people are finding that an intermittent fasting protocol, where they don’t eat anything for most of the day followed by one or two big meals works far far better for food control than the standard of eating many small meals per day. Again, this isn’t a universal and I’m currently examining differences between people to determine who will respond best to a given pattern.

I’d also note that there is a fair amount of literature that eating more frequently has benefits in terms of blood glucose control, blood lipid levels and other health markers. I’d add to that the recent work on caloric restriction and intermittent fasting (a topic I’ll look at in a later article) is finding massive benefits (especially for the brain) from less frequent meals. So even this topic isn’t as simple as ‘more frequent meals is healthier’.

However, this is all tangential to the claims being made for metabolic rate. Whether you eat 3 meals per day or 6, if your daily caloric intake is identical, you will expend the same number of calories per day from TEF. While work in rats and mice, for whom everything happens faster, has found that a single meal can lower metabolic rate, this is irrelevant to humans. Skipping a meal will not affect human metabolic rate at all.

Quite in fact, it takes at least 3-4 days of fairly strict dieting to impact on metabolic rate (and some work on fasting shows that metabolic rate goes UP acutely during the first 72 hours of fasting); a single meal means nothing. You will not go into ‘starvation mode’ because you went more than 3 hours without a meal. Nor will your muscles fall off as an average sized food meal takes 5-6 hours to fully digest, as I discuss in The Protein Book.

Now, all of the above is only looking at the quantity of weight loss, not the quality. For athletes and dieters, of course, sparing lean body mass and losing fat is a bigger goal than how much weight is actually lost. Which brings me to the boxer study that everybody loves to cite and nobody seems to have read (except me as I spent years tracking down the full text of the paper).

In this study, boxers were given either 2 or 6 meals per day with identical protein and calories and examined for lean body mass lost; the 2 meal per day group lost more lean body mass (note: both groups lost lean body mass, the 2 meal per day group simply lost more). Aha, higher meal frequency spares lean body mass. Well, not exactly.

In that study, boxers were put on low calories and then an inadequate amount of liquid protein was given to both groups and the meals were divided up into 2 or 6 meals. But the study design was pretty crappy and I want to look at a few reasons why I think that.

First and foremost, a 2 vs. 6 meal per day comparison isn’t realistic. As discussed in The Protein Book, a typical whole food meal will only maintain an anabolic state for 5-6 hours, with only 2 meals per day, that’s simply too long between meals and three vs. six meals would have been far more realistic (I would note that the IF’ing folks are doing just fine not eating for 18 hours per day).

Additionally is the use of a liquid protein that confounds things even more. Liquids digest that much more quickly than solid foods so the study was basically set up to fail for the low meal frequency group. They were given an inadequate amount of rapidly digesting liquid protein too infrequently to spare muscle loss. But what if they had been given sufficient amounts of solid protein (e.g. 1.5 g/lb lean body mass) at those same intervals? The results would have been completely different.

As discussed in The Protein Book in some detail, meal frequency only really matters when protein intake is inadequate in the first place. Under those conditions, a higher meal frequency spares lean body mass. But when protein intake is adequate in the first place (and again that usually means 1.5 g/lb lean body mass for lean dieters), meal frequency makes no difference. And that’s why the boxer study is meaningless so far as I’m concerned. An inadequate amount of liquid protein given twice per day is nothing like how folks should be dieting in the first place.

In any case, let me sum up the results of this review: Meal frequency per se has essentially no impact on the magnitude of weight or fat loss except for its effects on food intake. If a high meal frequency makes people eat more, they will gain weight. Because they are eating more. And if a high meal frequency makes people eat less, they will lose weight. Because they are eating less. But it’s got nothing to do with stoking the metabolic fire or affecting metabolic rate on a day to day basis. As the researchers state above:

We conclude that any effects of meal pattern on the regulation of body weight are likely to be mediated through effects on the food intake side of the energy balance equation.

And that’s that.

Practical Application
The take home of this paper should be fairly clear and I’m going to focus primarily on dieting and weight/fat loss here. I’m also going to assume that your protein intake is adequate in the first place; if you’re not getting sufficient protein during your diet, you have bigger problems than meal frequency can solve.

Before summing up, one last thing, from a practical standpoint, I sometimes wonder if the people who are adamant about 6 meals/day have ever worked with a small female athlete or bodybuilder. A 120 lb female may have a daily food intake of 1200 calories/day or less on a diet.

Dividing that into 6 meals gives her 200 calorie ‘meals’. More like a snack. 4 meals of 300 calories or even 3 meals of 400 calories is a much more livable approach than a few bites of food every 3 hours.

By the same token, a very large male with very high caloric requirements (for dieting or mass gaining for example) may find that fewer larger meals are difficult to get down or cause gut discomfort, eating more frequently may be the only way to get sufficient daily calories.

But again, these are all completely tangential to any (non-existent) impacts of meal frequency on metabolic rate or what have you.

So here’s the take home:

  • If eating more frequently makes it easier to control/reduce calories, it will help you to lose weight/fat.
  • If eating more frequently makes it harder to control/reduce calories, or makes you eat more, you will gain weight.
  • If eating less frequently makes it harder for you to control/reduce calories (because you get hungry and binge), it will hurt your efforts to lose weight/fat.
  • If eating less frequently makes it easier for you to control/reduce calories (for any number of reasons), then that will help your efforts to lose weight/fat

I personally consider 3-4 meals/day a workable minimum for most, 3 meals plus a couple of snacks works just fine too. High meal frequencies may have benefits under certain conditions but are in no way mandatory. And, in case you missed it the first time through: eating more frequently does NOT, I repeat DOES NOT, ‘stoke the metabolic fire’.

Comments

comments

41 thoughts on “Meal Frequency and Energy Balance

  1. Great article. I was having this conversation with my friend the other day. I am currently dieting and my friend was insisting I should be eating 6 meals a day. My point was that at the age of 40 I don’t feel like I can digest food quick enough to do this.

    I am doing a high protein – low carb diet and I feel that 3 meals, plus protein supplementation around training times is more than enough for me. I don’t experience any periods of hunger and the diet seems to be working fine.

    Great to see my feelings in print, keep up the great work!!!

  2. Protein Review,

    the ‘point’ you made to your friend is off unless you have some kind of gastric disease.
    More protein just takes a longer time to digest, it’s just that easy. No need to down shakes every second hour to “keep the amino’s flowing” or what have you.

    Great article, Lyle.

  3. Excellent post! I have often had a few meals a day and don’t start eating until late. I have always questioned the logic of eat lots of small meals. But this clarifies why this isn’t true.

  4. I like the info Lyle, and plan on reading your Flexible diet book to get more info. I’m really intersted in the fatsing protcals you mention in some of your books as well. As a strength coach woking 10-12 hrs days I find that I do very well with 6 small meals a day with 1-2 being snacks and Post nutrition (liquid) as I train up to 4x a week.

  5. Great article – since reading Brad Pilon’s Eat Stop Eat I have been freed from the dogma and am now no longer anxious if I miss a meal that I will suddenly get fatter and lose all my muscle tissue! I actually find that eating makes me hungrier, and when you are trying to keep your cals to 15-1600 that makes 6 meals far too small to be satisfying, and for smaller women it is just craziness. It angers me that we are so blinded by dogmn and fitness myths like this!

    Thanks for a great article – going to link to it from my blog…

    Caroline

    http://www.kettlebellebody.com

  6. Great to receive intelligent information. Just one thing. I have tried the bromocriptine and as suggested it made me feel lethargic and slightly disorientated. Is there anything else that you can suggest to replace.

  7. I too agree with what’s been said. I have found that small, frequent meals stimulate my appetite. From a psychological standpoint, I have found frequent meals to be far too consuming, causing me to constantly be thinking about the next meal. As a female athlete, I have found eating according to my hunger is a far better approach. In addition, I did a 30 day fast and I had no hunger at all and it did not impact my metabolism or body composition in a negative way.

  8. I have no doubt that eating 3000 calories or 2000 calories or less per day will not matter if you eat 2, 3, 4 or 5 times per day versus 6 times per day etc… Howvwer I would like to know what the effect of this is for a mass building diet. If you are at or below maintenance then meal timing should be relatively inconsequetial, But wouldn’t it make a bigger difference if you were eating 1000 or 2000 calories per day above maintenance and were interested in gaining the most muscle possible and the least amount of fat? Also what about a meals effect on the Anabolic/Catabolic status of the body, Again, if you are trying to lose weight it might be beneficial to eat less frequently since eating a meal with protien is anabolic and will convert nutrients into body tissue weather it be muscle or fat. Training intensity and your goals should nto be thrown out the window, nothing exists in a bubble, this information was based on individuals looking to lose fat. I think if you are trying to gain muscle you should probably re-consider the benefits of more frequent meals. Also Muscle itself is thermogenic and will help you burn more fat, if you are small and don’t have a good base of muscle mass, perhaps gaining a little before you diet down will help you achieve your goals. Just some food for thought, pun intended.

    V

  9. A few things

    1. a pound of muscle burns about 6 calories per day, the idea that adding muscle prior to a diet is a dead idea as this is irrelevant to metabolic rate. Even if you gained 3 pounds of muscle in those few weeks (good luck) this would only increase metabolic rate by 18 calories per day. Irrelevant. Please read “Initial Body Composition and Body Fat Changes” on this site for more details.

    2. There is less research on meal frequency and overfeeding. However, one interesting study (reviewed in my Protein Book) found greater lean body mass gains from 3 vs. 6 meals per day with the same calories. There is emerging data that it is possible to eat too frequently, that muscle becomes insensitive to amino acids and protein synthesis decreases. Again, detailed in my Protein Book. So it’s not as clear cut as you may think.

    3. There may be practical reasons for higher meal frequencies, especially for athletes with large caloric intakes as discussed in the practical application above.

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  11. The 6 meals a day propaganda, comes from the world of bodybuilding. Pick up any bodybuilding magazine and every other page is an advertisement for some sort of protein supplement. Then the next page is a nutritional guide, that says you should supplement with protein shakes 3 times a day, in between your 3 balanced meals. Your 6 meals a day, lines the 6 figure advertising contracts these magazines get.

  12. hello again, i have a question and if you can answer it and send it to my email address that will be okay because i might forget where i saw this website.. anyway my question is i eat only one meal a day and thats between 9am and 2pm i will usually have one meal and a snack and i exercise 4 days a week .What i wanted to know is this intermittent fasting? i used to be 160 pounds and started to eat this way and i lost 50 pounds . i just wanted to know if this is intermittent fasting?

  13. Question..

    I always thought that the big reasoning behind more frequent meals was that it kept your blood sugar from spiking, and thus kept your insulin levels low throughout the day, which is what you want, right? (according to Lyle’s UD 2.0, p. 31, which I’m reading now).

    I know that if I go more than 4 hours without eating, my blood sugar DOES spike (I get all sweaty, hungry, and irritable)..

    So I like to eat smaller meals, 5x a day to that end..

    What’s the flaw in my logic?

    I’m not saying Lyle or anyone else is suggesting I SHOULDN’T eat 5-6 meals a day..

    I just want to know if I’m right about the increased meal frequency = low insulin levels throughout the day..

    I also understand from reading UD 2.0 that eating very low carbs achieves the same end, and I’m doing that as well (currently on the RFL diet)..

    But I still get hungry and shaky every 3-4 hours, and that means I’m spiking, even with the low carbs, no?

    (I’m going to re-read and re-read this article till hopefully a light comes on, but if anyone cares to help me out? Please?

  14. While the science on frequent meals vs three squares may demonstrate no difference, i do not agree that eating six meals a day is either pointless, counter productive or to be dismissed so easily.

    Earlier this year i went about trying to lose weight, which in the past has been successful but never permanent. I went about eliminating sugars and eating six meals a day consisting of lean protein, wholegrains and fruits/vegetables. This protocol ensured no issues with hunger, prevented that overly full feeling that can make you lethargic and eliminated hunger induced overeating. In addition, the usefulness of consuming a nightime meal consisting of slower digesting protein and EFA’s has demonstrated benefits for reducing muscle catabolism and ensuring you don’t go to bed feeling hungry.

    I would also say that overlooking the psychological benefits of regular eating is also unwise as this is where success or failure in anything resides. With a meal always a few hours away, the chance of you grabbing ten chocolate biscuits in a frenzy is going to be reduced. I personally don’t see how someone can eat at 12pm and touch nothing for six or seven hours and not feel hungry. Perhaps there is more the meal frequency that the physical science of it and that the mental benefits are more than worth the extra effort.

  15. Words, they mean things

    “I personally consider 3-4 meals/day a workable minimum for most, 3 meals plus a couple of snacks works just fine too. High meal frequencies may have benefits under certain conditions but are in no way mandatory. And, in case you missed it the first time through: eating more frequently does NOT, I repeat DOES NOT, ’stoke the metabolic fire’.”

    Second sentence is the money sentence. I’m not denying any of what you wrote.

  16. Very informative post. Certainly questions the 6 meals a day theory. But I myself have been on 6 meal a day plan but not because of the reason that the body is getting constant influx of protein and other nutrients every few hrs but because the heavier a single diet gets (as it gets to be in a 3-4/meals per day) the more insulin response and this increased insulin has been linked to more fat storage.

    Would u explain this phenomenon if it holds any ground?

    N yeah i’m no science student but looking for a bodybuilding nutrition Guru (given the truck load of theories and counter theories on nutrition). lol

  17. great article

    what about the common thought of “eating too much food at once will make you fat”?

    i.e. is there any difference if you consume 2000 calories over 3 meals over the day vs. 1000 calories over 2 meals vs. 2000 calories over 1 meal?

  18. It all works out at the end of the day assuming that the daily calories are identical. As folks who are doing various interpretations of Intermittent Fasting are demonstrating readily, eating most of your calories all at once (or spread across 2 bigger meals) isn’t harmful and may be beneficial in some ways.

  19. Love the work here. Quickly, if my intake is approximately 1800kcals a day in an attempt to drop bodyfat, this would require me to eat over 80g of protein in a meal if i was to do the 3 meal approach (i am on six a day having 40g per feed at the moment). I would like to move to 3 meals, but am unsure as to whether eating that much protein is suitable. Cheers

  20. This is interesting, and I’m going to read this Warrior Diet which I’ve heard about before but didn’t realize was connected to fasting, but I’m not sure I could ever break the my “cherished” breakfast routine, for those that have implemented, how did you ever make it to midafternoon on fumes?

  21. This article is a breath of fresh air. I have always been scepticle of the eating every 2-3 hours plan. I always feel hungry and dissatisfied after eating and find myself back in the refrigerator an hour later. But when I eat a REAL meal im satisfied for most of the day. Also it is very hard to stick to a frequent meal plan with work, school, family , training and social time. Eating 2-3 larger meals is easy. So thank you putting evidence based scientific information into basic common sense to dispell the current ( commercially driven) mythe to rest. Not to mention I can train like an animal with the 2-3 meals, and feel weak when comsuming smaller meals. I think I will stick with 3 squares a day. Thanks again, really love the article

  22. Lyle – wonderful site; just came across it and this particular article.

    Question: If it’s a fact that the human body is capable of digesting only 25-30g of protein per meal, then wouldn’t eating only 2 meals be insufficient to spare and sustain lean mass as well as a positive nitrogen balance, and thus result in catabolism? Using the 1.5g/lb of lean body weight, that means a male with 135lbs. of lean BW consuming only 2 meals would need to take in over 100g of protein per meal. What am I missing???

  23. was asked by someone could a ketagenic diet be utilized while fasting for 30 days there is a window between 3am-9pm where he cant eat or drink but between 3am til 10am he will be sleeping anyway so energy expenditure is minimal in which the fasting window is smaller & due to fasting is body will fatigued similar to a ketosis state, i am wondering if a CKD is something he could utilize to manipulate his weight loss at the same time as fasting & training parameters he would use aerobic activity only or weight training to initially deplete carb stores

  24. is it considered IF if I eat like this:

    meal 1: 2-4pm

    post wo meal: 8-9

    16-20hour fast then do it again. I doesnt have to be based off of 24 hours does it? like I fast 20 hours then eat 1-2 meals in a 5 hour period

  25. Just writing for future visitors @Tim’s comment above about 30g protein per meal. Obviously this is bunk… for those that don’t want to read any more… if you really wanted to hit your protein/ your macros in one meal, you could do it and still build LBM. It is NOT a fact that the body can only absorb <30 g protein per meal.

    If it were true then all fairly religious Muslims would be skinny and malnourished, as they only eat for a few hours out of the day for a whole month every year. Back in the day, when we hunted animals and had no meat preservation methods we ate the crap out of some sabretooth tiger and then might not have eaten again for a few days.

    I believe Lyle has another article about the study that started this myth, if not I know leangains and A. Aragon do. If memory serves my correctly, one of the studies found no difference in new protein synthesis with ingestion beyond 30g… but these were fasted boxers who didn't train prior, and protein synthesis is meaningless… the indicator we care about is net muscle accretion at the end of the day/week/month (if protein synthesis is high, you can still lose muscle if catabolism is higher). Another found that 30g of whey was fully digested in 3-4 hrs… but it also found that casein was still digesting after like 8 hours.

    When you read something like this, think about it from a biological survival point of view… if the 30g per meal thing were true, the human race would be extinct, and hence it's not. Q.E.D.

  26. Sounds interesting, and I am tempted to try going back to a meagre 3 meals a day…however… I was 11 (70) stone 3 years ago, I’m now 15.5 (95kg). I have achieved this eating 6-7 times per day and training heavy and short.

    To drop to 3 meals a day would mean… splitting my current caloric/protein/carb/fat into 3 portions….which would be MONSTEROUS. I would need to consume about 1,500 Calories per sitting, 80-100grams of protein…. This is Waaaaaay to much in a sitting no?

    All I can comment on is what I have personally experienced. I am a big muscular guy now, which I never was before. In part this is due to the weight work, but as any experienced bodybuilder knows, you don’t grow in the gym, you grow in bed and in the kitchen.

    Comments/suggestions?

  27. For me changing the eating pattern to smaller meals more frequently over a period resulted into getting the feeling of full stomach with smaller amount of food. It was like my stomach has shrunk. I am not sure what went under the hood but after some time, I was not able to eat as much quantity at any single meal as I used to do before.

    I guess once you get to that stage, you can skip one or two of those frequent meals and that will help create a deficit.

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