What is the CICO (Calories In, Calories Out) Diet? How to Count Calories for Weight Loss

Yeah, it can be confusing when you don't understand CICO.

It’s time to learn about The CICO (“calories in, calories out”) Diet!

You probably have questions like

Steve, does CICO work? 

Will counting calories help me lose weight?

Okay, what the hell IS a calorie?

Well my friend, you’ve arrived at the right place!

I’ve been writing about this stuff for 12 years, and our team of coaches help their Online Coaching clients with all types of diets (including CICO). We are really flippin’ good at it!

Here’s what we’ll cover to answer the question: “What is CICO?”

It’s time to get started!

What Is the CICO Diet plan?

I guess this is kind of CICO, in a way

“CICO” stands for “Calories In, Calories Out.”

The CICO Diet is a weight-loss strategy where the participant tries to tip the balance of what they eat (calories in) against what they burn (calories out).

That’s pretty much it.

It doesn’t really matter what food you eat, because there are no restrictions on any specific food groups with CICO. 

It also doesn’t matter what exercise you do (if any).

As long as you get the equation right, and the calories you eat are lower than the calories you burn on a daily basis, you’re good to go.

Naturally, Barney would like CICO, because it doesn't forbid beer.

The CICO Diet is really simple and has helped quite a few people lose weight

This is likely why the CICO Diet has grown in popularity in the subreddit r/loseit

Is Losing Weight Really About Calories?

One way to lose weight is to be eaten, but I wouldn't recommend it.

Yes. Losing weight actually does come down to burning more calories than you consume.

It’s about as close to fact as we can get in nutrition science.[1]

As we address in our guide How to Lose Weight (The 5 Rules of Weight Loss), our bodies obey the Laws of Conservation of Energy and Thermodynamics: 

To lose weight, we need to burn more calories than we consume regularly. 

With this knowledge, it makes sense to design a diet specifically around this principle: match the calories you eat (in), with the calories you expend (out).

No other food rules need to apply:

As long as you meet your calorie goal, you can forget about the rules of any specific diet.

I can see why CICO might appeal to the Joker...

This appeals to me personally, because I’ve created my own guidelines for how to eat, and I don’t pledge allegiance to any particular dieting strategy.

Because I’m a mind-reader, I know your next question is likely…

Does Calorie Counting Work? (CICO and Weight Loss)

You can totally eat Dim Sum on CICO!

In principle, CICO works.

In practice, it becomes a little more complicated. 

Okay, fine, A LOT more complicated.

That’s because a lot of things influence “calories in.” 

Ditto for “calories out.”

Let’s break some of this down.

Here are some of the things that impact “Calories In:”

  • Appetite: how hungry we are is going to drastically affect how many calories we consume. Hormones, our body composition, and tastes and preferences will all impact our appetite.[2] 
  • Calories absorbed: the preparation of food will affect the bioavailability of calories. For example, cooking starches (like potatoes) generally increases the calories available.[3] Your own individual gut microbe can also influence the amount of energy extracted during digestion.[4] So will the macronutrient content of the food you eat.
  • Psychological considerations: your stress levels, sleep quality, and certain conditions like PCOS can all impact the regulation of hormones, which can influence your metabolism and appetite.[5]

Oh, and all of the above assumes we’re actually tracking calories accurately. Which pretty much nobody does. Ever. But I’ll get to that shortly. 

And remember, this is only half of the equation.

I'll be honest, I don't really know what's going on here...

Here are some of the things that impact “Calories Out:”

  • Energy burned while resting: your Basal Metabolic Rate is a count of how many calories you burn at rest and will be controlled by your age, weight, height, biological sex, muscle composition, etc. 
  • Energy burned through Non-Exercise Activity Thermogenesis (NEAT): do you fidget a lot? That increases your NEAT, or the energy you burn doing stuff other than exercising. Think tapping your feet, twirling your hair, using your hands when speaking, etc. Even just an hour of this kind of movement can accumulate an extra 300 calories burned.[6]
  • Exercise: of course, how much you intentionally exercise will impact your calories out, although perhaps not as much as most people think (more on this later).

This is only scratching the surface on what determines “calories in, calories out.”[7]

The important thing to consider here is that none of the above invalidate the basic premise of an energy deficit being necessary for weight loss. 

These factors will just influence one end of the equation or the other. 

For example, let’s chat about protein and CICO:

  • Eating plenty of protein has been shown to help keep people feeling full and satiated.[8] So lots of protein can help folks lose weight, not because it changes the requirements for weight loss, but because it might allow them to get through the day less hungry (lowering their “calories in.”)
  • Adequate dietary protein can help with building and maintaining muscle.[9] The more muscle someone has, the more calories they’ll need to maintain it (raising their “calories out.”)[10]

Read our guide “How much protein should I eat?” for more on this subject.

To recap this section: from a biological perspective, eating fewer calories than you burn is 100% necessary for weight loss. 

But all sorts of things impact the amount of calories we eat and the amount of calories we expend. 

This is going to lead us to….

The Problem With CICO (Humans Are Bad Estimators)

Yeah, humans (or LEGOs) aren't good at estimating calories.

The majority of the problems people have with CICO is that it allows nutrient-deficient food to enter the diet, only limiting “how much.”

They’ll argue that people should be eating fruits and vegetables, lean protein, avoiding processed foods, and blah blah blah… 

We all know this. 

You don’t need someone else telling you to eat your veggies.

Eating veggies for health is a no-brainer.

This isn’t the problem with CICO. 

The problem with CICO is it’s really hard to estimate “calories in” and “calories out.”

Like, REALLY hard. We humans are TERRIBLE at it. 

Take “calories in” or how much we eat: people generally UNDERestimate how many calories they consume by about 30-40%.[11] Even dieticians, who are specifically trained in nutrition science, underestimated how much they eat.[12]

Millhouse is probably just realizing the issue with CICO

“That may be true Steve, but don’t worry about me. I read the label on everything I buy so I know exactly how many calories I’m eating.”

Well, are you aware that the FDA allows a 20% leeway on total calories identified on packages?[13] Meaning that 100 calorie drink of Orange Juice might actually be 120?

If you’re a food manufacturer, which way are you going to lean towards? Especially when you know people might scrutinize the calories of your nutrition label in an effort to lose weight.

This isn’t just paranoia: this study found that packaged snack food generally contains MORE calories in it than advertised.[14]

Yeah…and remember, this is only half of the equation. 

It’s about to get even worse.

People are also really bad at estimating “calories out.” 

When folks self-assess how many calories they burned by exercising, they’re generally WAY OFF, by as much as 50%![15]

Oh, and those fitness trackers we wear? They’ve been shown to be inaccurate, some by up to 90%![16]

That’s why we made this infographic on tracking “calories out”:

This infographic shows calorie discrepancies from fitness trackers compared to actual calories burned.

This is the main problem with CICO: we’re stuck with educated guesses for “calories in” and “calories out.”

So we underestimate the calories we eat by 40%. And then we overestimate how many calories we burn by 50%.

No WONDER we think our metabolism is broken if we can’t lose weight!

The truth is we’re unknowingly eating too much, and/or moving too little.

Ugh.

Heck, even how many calories you need a day (your baseline or Total Daily Energy Expenditure) is an estimate, something we acknowledge in our calorie calculator, which you can play with right here:

THE NERD FITNESS CALORIE CALCULATOR

Total Daily Energy Expenditure Calculator
Male/Female
Use age in years.
Use pounds (lbs). If using metric system, multiple kg times 2.2 for lbs.
Use inches. If using metric system, divide cm by 2.54 for total inches.
Your BMR is an estimate of the total calories burned a day, while in a state of rest.
For "Activity Level," veer toward the side of less active. Studies consistently show that people are not as active as they self-assess.
Your TDEE is an estimate of the total calories burned during a single day, when exercise is factored in.

 

In summary: balancing “calories in against calories out” is really all quite messy when you get right down to it.

Does that make all this hopeless?

Not even remotely.

But it does give us some context if you can’t seem to lose weight.

Tips for Sustainable Weight Loss (Next Steps)

If your meal plate looks like this, you're doing a lot of the heavy lifting for weight loss.

This post is not made to dissuade you from trying The CICO Diet.

I actually encourage everyone to track their food and calories for one week, because it’s often an eye-opening experience on how much they’re truly eating.

If possible, take a few days and use a cheap food scale instead of just eyeballing it. You’ll be shocked an actual portion sizes of some foods!

When it comes to sustainable weight loss, here at Nerd Fitness, we encourage two paths:

  • Make small tiny changes towards “real food” (like the Nerd Fitness Healthy Plate above).
  • Make small tiny changes towards a strength training practice.

Both of these strategies can dramatically – and positively – influence “calories in” and “calories out” respectively.  

In our Guide to Healthy Eating, we explain why every website tells you to eat vegetables (which we also tell you): vegetables are full of nutrients, contain lots of fiber to keep you full, and are generally low in calories.

These image shows some real food, critical if you're trying to lose body fat.

Eating lots of vegetables, or “real food,” will help you naturally lower “calories in.”

How about another example to think about? Here are 200 calories of a blueberry muffin:

Yeah, you don't even get the whole muffin.

Compare it to 200 calories of broccoli (Thanks to wiseGEEK):

A pic of 200 calories of broccoli

Which one do you think you’re likely to accidentally overeat for your calorie allotment?

Right.

For our other strategy, our Strength Training 101 series explains why growing strong is important for fat loss: 

Building muscle takes a lot of calories (and so does maintaining it).

In other words, a stronger version of yourself will require more calories:

Miss Piggy pulling bars apart in jail.

This will naturally raises your “calories out.”

The trick with it all is the “make small tiny changes” bit.

We’ve seen over and over that small steps (eating one new vegetable a week, a simple bodyweight workout) create momentum. Over time, these small changes are the keys to permanently getting healthy.

The entire Nerd Fitness Coaching program is based on this premise.

So what should you do now? Pick a small change and get going!

Here are some options for a healthy new habit:

The most important thing you can do now: start!

If you wanna win a race, you need to start it!

The exact “small tiny change” doesn’t matter so much, just pick one you feel comfortable with and get going! Once that habit becomes sustainable, pick a new one! And so on and so on…

We’ve seen it time and time again here that this is the true path towards success.

Boom!

Still here? Want some more guidance? An exact plan to follow on where to go next?

Alright, you got it, but only because you’ve been nice this whole time.

#1) Our 1-on-1 Online Coaching Program: a coaching program for busy people to help them make better food choices, stay accountable, and get healthier, permanently.

You can schedule a free call with our team so we can get to know you and see if our coaching program is right for you. Just click on the image below for more details:

Your NF Coach can help you lose weight and get healthy!

#2) If you want a roadmap for getting in shape, check out NF Journey. Our fun habit-building app will help you exercise and eat better, all while you build your very own superhero.

Interested?

Try your free trial right here:

#3) Join The Rebellion! We have a free email newsletter that we send out twice per week, full of tips and tricks to help you get healthy, get strong, and have fun doing so. 

I’ll also send you tons of free guides that you can use to start leveling up your life too:

Alright, I think that about does it for this article.

Now, your turn:

What are your thoughts on The CICO Diet?

Do you have a strategy for balancing “calories in” and “calories out”?

Think I’ve got it all totally wrong? 

Let me know in the comments!

-Steve

PS: Make sure you read the rest of our content on sustainable weight loss:

###

GIF Source: Millhouse, Barney Thumbs Up, Joker, A Beautiful Mind, Leo “duh,”

Photo Source: A Surprise Performance Appraisal, Against the Current, There is always a bigger fish, Dim Sum Trike, miam miam

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72 thoughts on “What is the CICO (Calories In, Calories Out) Diet? How to Count Calories for Weight Loss

  1. Pingback: The Study Saga |
  2. I like this article, but I’m fairly proficient at estimating my macros, especially protein, so I tend to mostly do that, aiming for 100g/day since I weigh 150lbs., but at the moment I’m actually struggling to get enough calories so that my muscles can recover from 3x week strength training plus yoga on my off days, and generally carrying a 25lb one year old around, while still nursing. Basically I’m asking my body to do a lot, so I need to fuel it, but I’m needing to fuel in a healthy way, NO sugar for me!

    TL;DR I’m needing advice on how to get more calories in, in a healthy way, to build muscle and get stronger, and more like superhero me!

    -Taryn

  3. For two years with additive small changes, no change in measurements.
    I cut down to 2 alcoholic beverages a week from >7, no change in the measurements.
    I cut breakfast and didn’t add another meal later, no change in the measurements.
    I took up resistance training again, no change in measurements.
    Hell, I went on a 400 km hike through the Sierra Nevada over 30 days, eating the same or less than my older, much lighter, husband, who lost weight, and I still had no change in measurements!
    I have calorie counted before and if you don’t have a good relationship with food and your body, it can be a dangerous thing. It might be calories in vs calories out, but the reason these other diets win so many adherents is because cal in vs out feels f**cked.

  4. I have never heard of the CICO diet, but it’s essentially what I have been doing to lose weight for the last few months.

    I think there’s a problem with your logic in this post. I agree that people are bad at estimating calories, but I disagree that this is a problem.

    I tracked calories for 5 weeks, with no goal other than to track, and weighed myself weekly. I found that I was maintaining weight at an average of 3,100 calories per day. I cut that number by 15%, made that my target number, and I’ve been losing weight by steadily as a result.

    The point is that my calorie estimates might be wildly out, but as long as I have reduced them by 15% it doesn’t matter. Maybe I was maintaining weight at 2,800 or 3,500 calories, who knows? But as long as I’m tracking in the same way now as I did when I set my target then I will be eating a calorific deficit.

    So really, my recommendation for the CICO diet would be to forget TDEE calculators entirety, and track what works for your personally.

  5. Thank you for sharing. Like he said my emotions, and psychology have derailed my tracking. I obsessed with accuracy.. But you point out it is more about consistency then accuracy! Thank you!!!

  6. I feel you on this so hard. My partner never works out, eats and drinks more than I do, is older, and still has the same skinny frame he’s had since he was a teenager. I have tried to cut down my drinking significantly (at least I had before this pandemic), am eating less and better, work out 3x a week, and I’ve consistently gained 1-2lbs every year since my mid-20s. It’s sooo frustrating. I’m still a “healthy” weight for my age and height, but no matter how hard I work my muscles, the fat seems to always pile on regardless.

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