Weight Loss Tips: Disordered Eating, The Inaccuracy of TDEE, and the Limitations of CICO (LONG POST PLEASE READ)

Sections and important stuff in bold and sources and tldr at the bottom TW disordered eating discussion

I know I'll probably get downvotes for this, but please read. I want to say that this is a long post and a lot of people will disagree with me. However, I've seen some disturbing, unhealthy trends in this and other dieting communities and I would like to call them out because I've seen people be harmed. I have evidence (listed at the bottom) and would welcome others to refute me with evidence in the comments instead of just downvoting me so the post and the refutations have visibility. I recognize that I might be wrong on some of this, as I am not a doctor.

Introduction:

There are a couple of reasons I'm making this post. I see a lot of people arguing that their online TDEE calculator is a hard, infallible fact and ignore signals from their own bodies (ex: hair falling out/lethargy/sickness/and even LOSS of a period) because they trust the calculator over their own bodies and even their own doctor. I've seen people on the main diet subs get so obsessed with CICO that they count spice and medication calories and refuse to eat even if they're so hungry they can't fall asleep. I've seen people get into disordered mindsets because people on these subreddits treat TDEE calculators as a source of hard science and tell you that, if you don't stick to the calorie amount TDEE calculator tells you that you "need" to get down to, you can't lose weight. I've seen people say CICO is an "exact science" and if you disagree with any aspect of CICO, then you're suddenly a science-denier who needs to "get-out." The final reason I'm making this post is because a lot of children read these subreddits, and even though the sub seems to be good at telling minors they shouldn't diet severely, young teens and children are internet literate and will often emulate what you do. So we need to practice healthy weight-loss methods and not peddle pseudoscience and pretend it's reality.

I'm not telling you that you're a bad person if you follow TDEE calculators and that weight loss method has worked for you. I'm not arguing CICO has no utility. I am not arguing that intentional weight loss is bad in general. In fact, I am intentionally losing weight and succeeding, though I don't think that adds credibility to my argument in any way. Here's what I am arguing:

TDEE calculators are not an accurate reflection of energy expenditure and should not be used as a guideline for energy intake
Though calorie counting has utility, we cannot accurately predict our calories and saying that calorie-counting is a precise, exact science is wrong.
The dieting subreddit to eating disorder pipeline is real, and treating calorie counting as an exact infallible science contributes to that.

Part 1: TDEE calculators are not an accurate reflection of reality

So, let's start off with a basic question: where does the TDEE calculator come from? So, firstly, to my knowledge, there is no doctor-created TDEE calculator. TDEE calculators use researcher-based, peer-reviewed basal metabolic rate/BMR formulas (which calculate the calories burned by basic functions like breathing and cell repair,) and then they multiply that by a physical activity level (PAL). The most popular basal metabolic rate formula was created using indirect caliometry, a relatively accurate way to measure energy expenditure. So, if the BMR formula is accurate at measuring expenditure, then what's the problem with basing your energy intake on it?

Problem 1: Bioavailabilty

So, the BMR formula measures the amount of calories your body expends to maintain basic function. The problem is that we aren't able to metabolize every calorie we consume. Calorie counts on packages are based on how many calories are in the food itself, but our body can't utilize every calorie in every food. For example, a scientific study found that the body only metabolizes around 75 percent of the stated amount of calories in almonds!

And some people absorb more calories than others for weird reasons! For example, viruses. Scientists found that antibodies for adenovirus AD36 were found in 30 percent of obese individuals and only 11 percent of lean individuals. Though no causal link has been found, some theorize that certain viruses and bacteria can increase absorption of nutrients/calories in the small intestine, causing people to have different weights on the same amount of calories. So, energy intake's link to expenditure could very well highly depend on what viruses you've been exposed to.

Additionally, calorie absorption oftentimes depends on whether you're eating whole or processed foods. Whole foods take more energy to digest and are not as absorbed as well as processed foods, whose refined carbs and sugar are easy to digest and absorb. Different foods/different bioavailability. But you don't really utilize 100 percent of the stated calories in your food a lot of the time..

So, in summation, we don't absorb all the calories we eat. So we can't expend all the calories we eat. Therefore, a measurement of how many calories we expend SHOULD NOT be used to guide us on how many calories we should eat because it will probably underestimate what we really need.

Problem 2: Your Body Needs More Calories to Digest Things than TDEE calculators Say

So, your body needs a lot of calories to digest things. And TDEE calculators do take this into account. Kind of. One TDEE calculator I saw said that they account for digestion as 10 percent of the daily calories. The problem is that the amount of calories needed to digest vary wildly depending on what macronutrients you're consuming, as well as other qualities of your food.

For example, proteins require ten to twenty times as much heat energy to digest as fats! and this discrepencacy between how many calories are in the food itself and how many calories are actually utilized by the body is NOT accounted for on the packaging. So you're always utilizing less calories than you think you are if you eat a lot of protein.

In addition, food has different thermic effects on the body. The intake of certain nutrients (protein and carbs) increases energy expenditure more than fat, and calorie calculators don't take this into account.

Also also, fiber can slow digestion and prevent some calories from being absorbed altogether!

Overall, TDEEs account for digestion, but if you're doing high-carb or high-protein or high fiber or whatever, this digestion multiplier can be wildly inaccurate and you can be underestimaing your calories by A LOT.

Problem 3: You don't Actually Know Your Physical Activity Multiplier (PAL)

So far we've talked about two elements of TDEE calculations: the BMR and digestion. Now, let's talk about the physical activity level multiplier (PAL), a predictor of our exercise levels that is used in conjunction with BMR to estimate our daily energy expenditure. You can be either sedentary, lightly active, moderately active, or highly active in these calculators usually, and the descriptor you select has a HUGE impact on your TDEE estimate. Let's breakdown the issues with individuals estimating their own activity levels.

So, I see a lot of people who claim they're sedentary, and claim that they only need 1200 cals because of that. The problem is that we overlook a lot of physical activity. I've literally seen people who work out 7 times a week claim they're moderately active too.

The reality is that we're really bad at predicting our physical activity levels. One study compared participants' reported physical activity with actual physical activity and found that participants underreported physical activity on their surveys, and they mostly underestimated their light/moderate physical activities that are necessary for daily life. So, if you think you're sedentary, you might be exercising more than you think by just existing in your daily life. This doesn't even account for fidgeting, which can add a lot to daily energy expenditure depending on the person.

Other studies find that, while individuals underestimate their physical activity from their supposedly sedentary daily life, some individuals also overestimated the intensity of their gym activity. Fitbits and other devices can tend to overestimate the calories burned by some activities, while underestimating the calories burned by other activities. And, when we don't have a device, we're more likely to think we're exercising at the gym more vigorously than we actually are.

Anyone who has used a TDEE calculator knows that sedentary vs active expenditure estimates for the same height and weight are WILDLY DIFFERENT. So being able to accurately assess your physical activity is CRUCIAL for knowing if you're eating enough according to these calculators. The problem is that we're unreliable narrators. We are unable to accurately assess our own physical activities, either by overestimating or underestimating. And, if you rely on TDEE calculators, this can lead to overeating, or, more likely (if you claim you're sedentary,) undereating.

The Ultimate Problem: Scientifically Observed Energy Expenditure is Way More than these Calculators Say

There's a lot of misinformation out there. I've seen people undereat themselves into exhaustion and a bad mood because of a calorie count from a calculator. It's become regarded as accepted knowledge, and, dare I say, scientific fact on these subreddits, that these calculators are accurate and you need to abide by them or even eat less than the calculator tells you just to be safe.

So, you might be saying: "So what, forgottenellipses? Sure there's issues with bioavailability and digestion and underreporting/overreporting physical activity, but is there any HARD-LINE proof that TDEE calculators are inaccurate?"

I'm here to tell you that, even if you ignore my other points, there's rock solid proof that TDEE calculators are not aligned with reality.

So, let's first look at what the calculator says that I should be eating a day to maintain my weight. I am female, age 22, 5 foot 5 and 170 pounds, "lightly active" (I guess, but that's unreliable) with a BMI of 28.3. The calculator says I should be eating 2,106 calories to maintain my weight. If I eat more, I gain weight. If I eat less, I'll lose weight.

Right??

Well, there's a way that's more accurate than an equation to estimate daily caloric expenditure. And it's called the doubly labeled water method, which is used by scientists to measure caloric expenditure. Aside from a metabolic chamber, it's the most accurate way to measure caloric expenditure. The "gold standard." (Westerterp 2017). While TDEE is a vague estimation, doubly labelled water method is close to reality.

Let's look at one doubly labelled water study to see how many calories are actually burned for the average person. First study, by Tooze et al in 2007 looked at 450 men and women with variety of BMIs, with a relatively equal amount of participants in each BMI group for women, and a larger amount of overweight subjects for men. The average Physical Activity Level was 1.75 for women (which is the average America PAL in general according to other studies) and slightly lower for men.

https://academic.oup.com/ajcn/article/86/2/382/4632961

Total energy expenditure for the average woman:

"2308 ± 33" cals/day

For the average man:

"2899 ± 30" cals/day

That's over 200 cals more than my calculator said--and this doesn't even take into account that my energy expenditure is probably higher than that, since I'm more overweight than the average member of that study.

I can link more studies if asked, but I thought this was a pretty robust one and didn't want to re-find other studies that I've seen in the past.

The bottom line? Your body is not a machine, and a TDEE calculator can't accurately depict your needs.

The Problem with TDEE Calculators being Your Bible

Okay, this is just my opinion, but I see a lot of CICO-ers justifying diet practices that harm their body because the calculator said it's okay.

"The calculator said that I need to eat 1200 to lose 2lbs a week, so I'm going to push through the lethargy that I'm feeling because it's healthy. It's science!"

"I feel so hungry, but I've hit my limit for today! (according to what the calculator says my deficit should be.)"

"I'm 15 years old, and it's hard to follow my TDEE calculator. I feel like I'm starving! What's wrong with me?"

I've seen variations of the above on dieting subreddits. And it's just sad to me. Because an individual cannot accurately gauge the bioavailability of their diet, the amount of calories it takes them to digest their food, or their physical activity levels. So how can TDEE calculators be complete scientific fact when there are so many unknown variables?

And, additionally, a robust study SHOWS that we burn more than TDEE calculators claim. So why do we have so much confidence in this imprecise calculator that we're literally willing to ignore our own bodies in order to follow the calculator's precise guidelines?

If you feel malnourished, adjust your diet. If you're having physical signs of malnourishment, you need to adjust your diet. There is no hard and fast rule for how many calories is enough for you, and we need to stop arguing that CICO is such an exact science that everyone has to adhere to in order to lose weight and be valid. Because when we encourage people to listen to the calculator, we might be encouraging them to starve. We don't know them or their body, and we are not doctors.

Part 2: The Limitations of CICO

"Calories-in, Calories-out. 3500 calories in a pound. Just read the back of the box. Just weigh the food on the scale. That's all there is to it."

I think you know by now that it's more complicated than that. I mean, we've previously discussed how bioavailability varies among foods and among body types. And we've also discussed how different macros take more calories to digest. But still, CICO can be very useful. Knowing the calories that are estimated to be in things can be useful because, of course, calorie intake is the most accurate predictor of weight. Calorie counting, when not done obsessively, can help someone have a ROUGH gauge of their daily intake. But does this mean that calorie-counting is an exact science?

No. Because we're shitty scientists.

Problem 1: We are Unreliable Narrators and Don't Report Our Calories Accurately

So, most people underreport calories. By a lot. One study found that the average person underreported calories by 429 calories per day. Other studies found similar underreports of calories. Even if you know a lot about calories and nutrition, you are still fallible to underreporting. One study found that dieticians ate 223 on average MORE calories a day than they reported for the study. This amount of underreporting is significant, and it alone proves that CICO cannot be handled by the average person as an exact science.

But some people overreport calories. Namely, people with restrictive eating disorders. One study found that people clinically diagnosed with anorexia overreported their caloric intake by 16 percent of their daily intake, which was a statistically significant amount.

So, what's the problem with this? Well, for one thing, it renders the specifics of calorie-counting pretty useless. What's the point of counting spice and medication calories if you're underreporting by hundreds of calories a day? What's the point of weighing everything you eat? What's the point of denying yourself a healthy snack when you're cripplingly hungry? Despite your math, apps, and numbers, you have no idea how much you're actually eating.

But there's a bigger problem here. That being, the tendency for individuals without eating disorders to underreport, and those with restrictive EDs to overreport. I know for a fact, anecdotally at least, that TONS of ED people lurk on this and other subreddits. You could have someone without a restrictive ED who claims to eat 1200 cals a day but actually eats 1600+ cals per day talking about and showing pics of their healthy weight loss online. Meanwhile, someone with a restrictive ED could see that 1200 calorie recommendation and, in an attempt to emulate that, end up eating 1100 calories or less while THINKING they're eating the same as the people who are underreporting their calories. And then the person with the restrictive ED ends up experiencing symptoms of malnourishment and wondering why they're experiencing these symptoms and others are healthy, when they're supposedly eating the same amount of calories. So, you end up having an echo chamber of people who say restricting themselves to "x" number of calories is healthy--because they're actually underreporting. And then the people who overreport end up eating that amount of calories and end up being super malnourished.

Problem 2: Calorie Counting Exactly and Obsessively isn't Sustainable and Telling Others That They Have to Do So Sets Them Up for Failure

So, a commonly accepted fact is that successful weight loss has to be sustainable. If you can't maintain the weight loss habits, then you can't maintain the weight loss.

Okay, this is just my opinion and isn't really evidence-based, but, I see the kind of hyper-specific, obsessive calorie counting that some people engage in, and it doesn't seem sustainable to me. Are you going to refuse food at social gatherings forever? Are you going to refuse to go to the Mom and Pop place because it's not a chain restaurant and doesn't have calorie counts? What about visiting or even living in other countries where calorie counts aren't standard? There are so many situations where you don't have the time, opportunity, or ability to count calories. It seems sustainable enough to sometimes count calories, especially if you're the one preparing the food, but counting every day obsessively just seems like it wouldn't work out long term. And I feel like you'd miss out on a lot of opportunities.

Point 3: The Diet Subreddit to Eating Disorder Pipeline

"But, forgottenellipses," you might ask, "what's the big deal, and are you really such a loser that you wrote a thousands of words treatise on the limitations of calorie counting and TDEE calculators when there's no real impact?"

Yes, I am a loser with nothing to do, at least for this week-long break between my jobs. But there is a real impact to what I'm saying, and I think the time I spent on this post is worth it.

The impact? Well, the cult of CICO, the belief that you can exactly and stringently count every calorie, is incredibly dangerous to those prone to disordered eating.

First, I do acknowledge that the lowest amount people eat here is 1200cal, and most websites say that's the safest lowest amount for people. But for some people that's not a safe amount, even if they're short and sedentary. Anecdotally, imma level with y'all and say that I have disordered eating (restrict and binge), and a lot of people on eating disorder subreddits say they became underweight and had negative health effects at 1200cal, and that their foray into eating disorders began with a very popular subreddit associated with eating that amount of calories. I won't link the eating disorder subreddits here bc I don't want to introduce people to that content. Just believe me.

So it's not plenty for everyone.

In addition, in the Minnesota Starvation Experiment, which strived to understand starvation so that American soldiers could rehabilitate Holocaust survivors, men were fed a semi-starvation diet of 1500 calories a day. I've seen a lot of men on this subreddit eat around that or less. Even men eating 1200. Just know that, after the participants in that study became gaunt and malnourished because of their diet, they regained all of their weight after the starvation period concluded.

But the low calorie amounts aren't the real reason for the diet subreddit to ED pipeline. It's this idea that CICO is a pristine, unblemished science, that you can control your life and your weight by pure mathematics, that there are no errors in calorie science if you just try hard enough and read the packaging and weigh all your food.

This is a bad mindset. In order to understand why, we have to look at the root causes of eating disorders.

According to an article by the staff at the McCallum Place, a center that offers rehabilitation to those with eating disorders, "the symptoms of anorexia [are] correlated with an individual’s underlying sense of powerlessness in the face of life’s stressors, and a general lack of control." This is a commonly articulated belief in the restrictive eating disorder community. Restrictive eating disorders aren't about vanity or even just about being skinny. They are often about control. Controlling your body by willing it into submission and by starving it into smallness.

And what is a better external sign of your control than a number? What is more exact and precise and always the same? Body dysmorphia may make you seem fat no matter what you weigh, but numbers are always the same. And if we treat CICO like an exact science, if we tell others that CICO is always perfect, and that they can only lose weight by hyperfocusing on these numbers, then obsessing over calories seems like a perfectly evidence-based way to control your own body.

The reality is that CICO is wildly inaccurate. It doesn't offer control. It's, at best, a rough guideline. And YET, people treat it like the literal Bible and structure their days around making low-cal meals. People are counting their lettuce cals. People are counting their spice cals. People are counting the cals in Tic-tacs. People are eating 1200cals, and count their alcohol in that super low caloric amount, meaning they're malnourishing themselves foodwise to get drunk. Despite the fact that we will overreport or underreport our calories, people treat their calorie limit like a hard and fast rule rather than a rough guideline. If we recognized that CICO is fallible, if we recognized that we are shitty scientists and have no perfectly accurate gauge for how much we eat, maybe us and those prone to eating disorders wouldn't feel the need to obsess and track every calorie, because we would know the effort to truly know our daily intake and exercise control over our bodies is absolutely futile.

A lot of people with EDs are aware of the failure of CICO as a hard science, I'm not pretending I came up with the idea. But the obsession with CICO and the prioritization of CICO over every other dietary lifestyle (including, puzzlingly, eating healthy and whole foods), really does encourage the disordered mindset and prioritize numbers over health.

I think it's time to reconsider our approach to diet and health in general. I welcome any and all discussion.

Evidence

TDEE Calculators