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 13 years, and our team of nerdy experts help our 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?”
What Is the CICO Diet plan?
“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.
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?
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.
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)
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, body composition, and our 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.
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 number of calories we eat and the number of calories we expend.
The Problem With CICO (Humans Are Bad Estimators)
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.
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]
“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 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
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)
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 about the 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.
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:
Compare it to 200 calories of broccoli (Thanks to wiseGEEK):
Which one do you think you’re likely to accidentally overeat for your calorie allotment?
Right.
For our other strategy, the 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.
And will be able to escape from jail easier.
This will naturally raise 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!
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.
Here’s how Nerd Fitness can help:
#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:
#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:
Download our free weight loss guide
THE NERD FITNESS DIET: 10 Levels to Change Your Life
- Follow our 10-level nutrition system at your own pace
- What you need to know about weight loss and healthy eating
- 3 Simple rules we follow every day to stay on target
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:
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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,