Is Fat Loss Actually this Simple?
Calories in vs. Calories out. Exploring factors affecting the CICO model.
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Fat loss is often described as a ‘simple’ equation. The argument is, if calories in, are less than calories out, you will lose fat (Calorie Deficit). This is called the CICO model or Calories in Calories Out model.
This certainly simplifies fat loss, but how true is it?
The CICO Model.
Cico operates on the principal that your body’s calorie output, needs to be somewhat equal to your input, in order for weight to stay the same.
An easy way to visualize this is to think about a seesaw, if both ends are equal the seesaw doesn’t move, but if one end is heavier than the other, the seesaw rises in one direction.
The left of the seesaw or TDEE (Total Daily Energy Expenditure) is made up of a few different things.
BMR – Basic Metabolic Rate. This covers all metabolic processes that occur within the body in order to keep you alive. You’d still burn this amount of calories even if you sat in a chair all day!
NEAT – Refers to Non-Exercise Activity Thermogenesis. In other words, this is fidgeting, walking to the fridge, ironing, hoovering etc.
EAT – Exercise Activity Thermogenesis. Calories burned from exercise.
TEF – Thermic Effect of Food. Calories burned from the metabolic energy required to consume food.
If Calories Consumed i.e. eating and drinking is higher than TDEE – the seesaw will dip towards GAIN. According to this model, this means you will gain weight.
If Calories Consumed is less than Total Daily Energy Expenditure – the seesaw will dip towards LOSE. Meaning you will lose weight.
Now the CICO model isn’t just a theory. Calories in and out are a crucial component of fat loss.
So, is a calorie deficit the ONLY thing you need to lose fat, or are there other factors at play?
Well…our bodies are pretty complicated and the reality is, there are in fact other important things to consider when trying to lose/gain/maintain your weight.
Let’s deal with these factors individually.
Hormones
What are hormones? Hormones are chemical substances that are secreted in order to control and co-ordinate certain metabolic processes. Think of them like messengers that trigger certain events.
Your body has a state that it LOVES to be in. This is called homeostasis.
Now homeostasis is kind of the perfect state for us, but we constantly move out of it. Whenever this happens, the body likes to bring things back to the ideal.
Hormones play a large role in this.
Let’s talk about some of the hormones that can affect your body fat percentage.
Insulin and Glucagon
Thyroxine
Cortisol and Non-adrenaline
Insulin
What is insulin? Insulin is a substance produced by your pancreas that is released in reaction to blood sugar levels rising. People who struggle or are unable to make their own insulin are Diabetic, therefore cannot control their blood sugar levels.
The opposing hormone to insulin, is glucagon. This raises blood sugars.
Insulin and glucagon work together in order to prevent your blood sugar rising too high or falling too low.
When you digest food that contains glucose (sugar), your blood sugar rises. In response your pancreas releases INSULIN.
This lowers your blood sugars by allowing glucose to enter the cells in your body.
Sounds complicated I know but all you need to know is…
High Blood sugar = Insulin released
Low Blood sugar = Glucagon released
Now Insulin will do a few things on top of this:
- It will inhibit lipolysis – this is a process whereby fat is released from fat cells and broken down.
- It will increase lipogenesis – this is the willingness of the body to store fat.
Now, before you go and call Insulin the bad guy. He really isn’t.
Inhibit certainly doesn’t mean STOP. And we need insulin because if it wasn’t present, blood sugars would keep rising and we’d go into hyperglycaemic shock (That’s the medical term for when our blood sugar gets so high that we go into a coma and if untreated we can die).
Also remember, when insulin is released, glucagon also has to be released in order to bring the blood sugar levels back to normal after insulin has done its job. And glucagon does the opposite of insulin, it increases lipolysis and decreases lipogenesis.
Let’s talk about Low Carb Diets.
Carbohydrates are broken down into glucose, therefore…when you consume carbohydrates, insulin is released.
The idea is that if you consume less carbs, you produce less insulin and you are more likely to lose fat.
Unfortunately, there’s little point to this.
First of all, eating lower carb doesn’t prevent you from gaining fat. Even though insulin does inhibit lipolysis (Break down of fat), the results of this are fairly minimal (assuming you eat a fairly balanced diet – I’ll go into this more in a moment)
The reality is, for most people, insulin levels will not affect CICO.
That means, whether you are low carb, or you eat higher carb, as long as you’re in a calorie deficit, you will lose fat (Lipolysis will still outweigh lipogenesis)
Now…there are a few exceptions.
For example, if your diet is extremely high in sugar.
Look at the graph below. The blue line represents a high glycemic index response (rapid digestion of sugars) and the red line represents a low glycemic index response (slow releasing sugars).
Think of this like the difference between a slice of bread and a sweet potato.
If you eat a balanced diet, you’ll have a mixture of the lines below, sometimes blue, sometimes red. Overall this will balance out. It’s also important to note, that if the same net amount of carbohydrates are consumed in the blue example as the red example, the insulin released ends up being the same, due to a sharper decline of blood sugar following the High GI food.
If however, your diet is high in sugar and you’re constantly snacking on sugary foods.
Your chart will look more like this.
Not only will this make you feel like crap (These sudden drops will make you crash and feel tired, moody and potentially give you a headache) you are also more likely to eat something else sugary to pick you up. This makes it more likely that you’ll overeat and thus…not remain in a calorie deficit.
Plus, your insulin levels will be high for a prolonged proportion of the day which can actually negatively affect your bodies capacity for lipolysis and cause you to be more resistant to a calorie deficit.
To sum up: Eating a diet too high in sugar can actually negatively affect your fat loss efforts as it leads to a higher concentration of insulin levels over time HOWEVER if you eat a fairly balanced diet, you don’t need to worry about your insulin levels or your carbohydrate consumption.
Thyroxine.
Let’s talk about the elephant in the room. Thyroid problems are pretty much always blamed as the main reason why people hold on to fat.
Is it true? Can this little gland really make or break your dreams of a lower body fat percentage?
The answer is yes. But don’t go blaming your thyroid straight away.
Hypothyroidism, which means your body doesn’t produce much of the hormone thyroxine, essentially causes reduced metabolic efficiency. In other words, your BMR decreases.
Reminder: BMR = Basic Metabolic Rate
As we know, your BMR is the largest contributor to your TDEE (Total Daily Energy Expenditure). Therefore, if it drops, we need to either add in additional movement OR decrease calories consumed.
Now, although there is a CORRELATION between low thyroxine and obesity, that doesn’t mean that every obese person has thyroid issues. Nor does it mean that every person with thyroid issues is obese.
In fact, some studies have hinted that the opposite causation is actually in play, i.e. obesity leads to hypothyroidism.
In short – Although having hypothyroidism or issues with the thyroid can be a factor in struggling to create a negative energy balance (i.e. a calorie deficit), it definitely doesn’t mean you CAN’T lose fat, nor does it mean you can’t achieve a lower body fat percentage…
On top of this it certainly doesn’t affect the CICO model, it just means your daily energy needs are lower than someone who doesn’t have thyroid issues.
In reality, for most people, the reason they are not losing fat is probably NOT because of their thyroid.
See my article on how to lose fat if you want to learn a little bit more about this. HERE.
Cortisol
When our bodies sense danger, the ‘fight or flight’ response is triggered.
This causes a chain reaction:
- The sympathetic system sends signals to the adrenal glands, resulting in epinephrine (also known as adrenaline) entering the bloodstream.
- As epinephrine is pumped around the body, the physiological reactions are immediate. The heart rate increases, blood pressure goes up, breathing becomes more rapid, extra oxygen is sent to the brain, senses become sharper, and glucose and fat are released in order to grant additional energy.
- After the initial surge of epinepherine, the HPA axis is triggered (This is the hypothalamus, the pituatary gland and the adrenal gland).
- If danger is still perceived, the hypothalamus (by releasing a hormone) triggers the pituitary gland (which also releases a hormone), which triggers the adrenal glands – causing the release of another hormone…this is cortisol.
- This keeps the body on ‘red alert’.
What does all this mean? Well essentially, when you’re stressed, there’s not only a mental reaction (that feeling of stress) but there’s also a physical reaction. People who experience anxiety will find during episodes that their heart rate increases and their palms sweat – this is the stress reaction. When this occurs, a hormone called ‘epinepherine’ is released, and this causes a chain reaction, resulting in another hormone, ‘cortisol’ being released.
Still with me? Good, because the only thing you need to know, is that when cortisol is present, the body is stressed.
Now…usually, following a ‘stress’ reaction, the next step would be for cortisol levels to drop and the parasympathetic system to trigger.
Think of this as the ’emergency brake’. This stimulates important processes in the body that affects things like digestion, breathing, arousal, lipolysis and tissue repair.
So…what happens when the emergency brake stops working?
Chronic stress has an extreme effect on the body, and though this does in fact stimulate the deposition of fat, it also has more serious implications, for example, increasing the risk of heart rate or stroke. Think about the processes I mentioned above, these won’t be occurring properly if the body stays in a stressed state.
So how does it affect CICO?
When cortisol is in our body at a high level, for a prolonged period, various things happen that can affect our body fat percentage.
Though cortisol sometimes decreases appetite, most of the time it increases, meaning we’re likely to consume more calories – and of course according to CICO, that means we’d have a higher chance of gaining fat.
On top of this, cortisol increases lipogenesis, storing extra nutrients as fat in order to keep energy stores high and accessible.
The flipside of this, is that it makes it harder for us to lose fat, and we can become more resistant to a calorie deficit.
If you suspect your cortisol is chronically high, rather than trying to circumvent a way around it in order to lose fat, you’re better off addressing the reasons why.
Work can be stressful, school can be stressful, kids can be stressful, life can be stressful. It’s important to spend time doing things just for you, and more than that, making sure you take at least 5 minutes a day to get in touch with your breath, and try to relax your mind.
Practices like meditation, yoga and even cardio can greatly assist with this.
Diaphragmatic breathing is really important if you want to trigger the parasympathetic system, so taking care not to breathe into your chest and shoulders is really important.
Gut Bacteria
In recent years, more and more scientific research has been focused on the gut.
Your gut, which comprises of your stomach, small intestine and large intestine, is filled with over three trillion bacteria! But don’t panic, these bacteria do a lot of great things for our bodies and they are (mostly) good for us!
Many articles could be written just about the gut, and gut bacteria, but as the focus of this article is on fat loss, let’s talk about how gut bacteria come into this.
There are billions of types of bacteria. You pick these up as you go through life, from the second you are born until the second you die. Gut bacteria are like DNA, no two people have exactly the same. The concoction of bacteria in your gut is a special mix just for you.
The gut biome can actually weigh up to a wapping 2kg!
So, what do our gut bacteria do? Well, lots of things actually.
Did you know that the kind of seaweed used in Japanese cuisine to make Sushi is actually broken down by a specific bacteria??! - If you haven't inherited this bacteria, sushi might mean pretty severe bloating for you...
We also receive nutrition back from our gut flora – they provide us with nutrients & they can also partially digest food for us – this is what yoghurt is! Gut bacteria can actually secrete biotin (Vitamin H) which is involved in vital metabolic processes such as synthesising carbs and fat for the body and breaking down proteins. It’s also great for shiny hair and strong nails.
The big question is, can your gut bacteria make you fat?
Some bacteria are greedier than others. If you have ‘chubby bacteria’, it means your bacteria extract more energy from the foods you eat. In other words you could be consuming more calories from the same amount of food, than someone who doesn’t have this bacteria…
In studies performed on rats, scientists introduced 'chubby' bacteria into the gut biome of previously underweight rats. On the same diet as before the rats gained weight.
Interestingly, it’s unclear whether these kind of bacteria lead to obesity, or if the two events are congruent (A higher body fat percentage will correlate with higher numbers of this bacteria HOWEVER it’s completely unclear which phenomenon influences which.)
The food we eat also affect the activities of bacteria. For example, if you eat a piece of fruit, this will likely attract bacteria that will manufacture fatty acids for the gut and liver. In comparison, if you eat a chocolate bar, it might attract ‘full body feeders’.
Similarly, if you eat a very high fat diet, sometimes gut bacteria can make their way into the bloodstream. This can result in the bacteria attaching themselves onto the liver or fatty tissue itself, and encouraging the deposition of fat.
It’s important to state, that ‘chubby’ bacteria can’t cause you to gain weight on their own.
So, how does this affect CICO?
If you happen to have ‘chubby’ bacteria (and we won’t really know if you do), it really isn’t the end of the world. That’s because our bodies are pretty great at handling slight variations in calories. This refers to the ‘maintenance range’ as it’s sometimes called, and without going into too much detail, essentially means that you can maintain your weight at a range of calories, not just a specific number.
Here’s the biscuit…if you have problems with your gut, the chances are it’s going to be affecting a lot more than your weight. Our gut is super important for a lot of reasons, and there are arguments that it can be the cause of depression, anxiety and fatigue (among other serious things).
Making sure you eat adequate fibre, and introduce some fermented foods into your diet is a good start. Even though research is still pretty undecided on how much these help, it has been proven they don’t hurt, and that’s a good enough reason to give it a try.
Bringing it all together.
The reality is, although the CICO model is accurate and undeniably true, it oversimplifies a lot of things.
Our bodies are pretty complicated, and there are a lot of factors that can affect our metabolism (BMR).
Hormones play a role in our sensitivity to calories, and undeniably affect lipolysis and lipogenesis (breaking down and storing fat).
On top of this, our digestive system, and it’s many helping hands (gut flora) is completely unique to us, and it may be that we take in less, or more calories than we think when we consume food.
Importantly, Calories in vs. Calories Out, doesn’t tell us the whole story. When we consider that we all have a unique, ‘maintenance range’, guessing our BMR and subtracting the popular ‘500 kcal’ might not be enough to get us over the edge and into ‘Lose’.
A final point, is that weight loss, does not mean fat loss. A calorie deficit creates weight loss, that’s for sure, but do you want to lose ‘weight’ or do you want to lose ‘fat’? If you want to preserve your muscle [ and remember, more muscle = more calories burned at rest], there are other important things to consider. That being said, this article isn’t about ‘how to lose fat’, so I’ll leave that there, for further discussion in another piece.
A note of acknowledgement for the missed talking points.
I could write a book on this, and it probably still wouldn’t cover everything. In fact, a book could be written about every single one of these talking points, maybe more.
For that reason, I’ve missed out on a few things. Hormones such as testosterone and estrogen, leptin and grehlin, infection and inflammation, the idea of IIFYM, micronutrients and many more important topics that didn’t quite make the article.
This isn’t to say that they aren’t relevant factors, I have just chosen to talk about the ones that are easier to comprehend and will make the most sense for the most amount of people.
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