Are all calories equal?
As somebody who has worked in the weight loss/weight management field for the last 13 years, I’ve pretty much heard it all as far as calories are concerned.
“I’ve been in a calorie deficit for a few weeks now but not seeing any weight loss, it must be my slow metabolism…my mother has a slow thyroid so it must be impacting me too”.
“I’ve been counting calories but I’m also super stressed and not sleeping well, my cortisol must be really high and therefore counting calories doesn’t work for me”.
“I’ve been told that my insulin and glucose levels are high and that’s why I can’t lose weight, it’s because my sugar levels are high”.
At this stage of my career, I feel qualified enough to dissect this ever-confusing topic of whether all calories are created equal.
Today I’m going to break it down for you once and for all.
It’s likely going to be a long and slightly technical one, so I hope this isn’t bedtime reading for you, unless you’re that way inclined.
First up, a clear explanation of energy balance.
Counting calories is not the same thing as calories in vs calories out.
I repeat.
Calories in vs calories out is NOT the same thing as counting calories.
Many people believe that just because they’ve totted up their calorie intake into Myfitnesspal over a few days/weeks that they should see weight loss as long as they have followed a calorie deficit (that number that they’ve likely pulled off the internet).
Here’s why this is never an exact foolproof formula to follow blindly.
Energy balance = calories ingested minus calories expended.
The calories in part is the simple part, it’s literally all the calories that you’ve put in your mouth and ingested, but even still, this trips up many people.
Most of the time because people like to estimate.
They ballpark guess how much cereal they’ve had, or how much peanut butter they’ve spread.
These two items are notoriously known for being deceivingly calorific per portion and awfully easy to be inaccurate with.
Ever tried guessing how much cereal you actually have in your bowl?
It’s actually depressing how little you get in a standard portion.
Then there are food packaging/labels, which are allowed to have an error margin of 10% - give or take.
Meaning if you have tracked a handful of nuts as 100kcal, it could be 90 or it could be 110.
Lastly, people forget what they’ve eaten.
The little bit of food whilst you were cooking, the little swig of juice after breakfast, or my personal favourite, the butter you spread on your toast or the oil you used to cook your eggs in – they ALL count.
So, I think that most people with any common sense can agree that these small but significant inaccuracies when it comes to calculating the ‘calories in’ part of energy balance is a) easy to do, b) easy to dismiss and c) can have a profound impact on your weight loss efforts.
The calories out part of energy balance however, is where it can get slightly confusing.
Rather than just the one thing to calculate as with the calories in part (what you ate and drank), there are 3 parts (or 4 depending on what textbook you’re reading).
1. Basal metabolic rate (BMR) – which accounts for about 65% of your calories burned
(Your BMR, the largest chunk of the pie is all the internal processes that are happening inside your body 24/7, 365 days a year. From your heart beating, to your body regulating your body temperature to your immune system keeping surveillance of potential attackers).
2. Movement (Non-structured and structured exercise) – this is about 25% of total calories burned.
(No need to expand on this too much, this essentially includes all of your daily movements, from the steps you take, to your exercise sessions to the hand gesticulating when you are speaking to someone).
3. Thermic effect of food (TEF) – this is about 10% of total calories burned.
(Thermic effect of food is simply the amount of calories you burn digesting your food).
So, let’s give a real life example to put this into context.
Mary is 50 years old, 160cm and weighs 70kg.
A simple online calculation will tell us that her BMR is 1289 calories.
Let’s say she does 5,000 steps and exercise 3x a week. That’s another 300 odd calories a day she’s burning.
Let’s say she burns another 50 calories a day digesting her food.
1289 + 300 + 50 = 1639 total daily calories burned.
On paper, eating less than 1639 calories per day will induce weight loss, but as we saw earlier, tracking calories ingested can actually be quite difficult if you’re not super diligent.
The first BIG take home message of this article is the following:
Just because tracking calories accurately can be difficult, doesn’t render energy balance (calories in vs calories out) useless or malfunctioning.
It’s more likely that you assumed you were in a calorie deficit whilst all along there were some inaccuracies taking place with your calories in side of the equation which left you in calorie maintenance.
Now that we’ve covered the calories in side, let’s have a look at how there could be inaccuracies with the calories out side.
To help with this, I’ve got 4 typical hypothesises here that I’m going to dissect to see whether there is any truth in them.
Here we go.
Hypothesis #1 – My thyroid is sluggish.
Hypothyroidism is a condition affecting the thyroid gland that heavily impacts metabolism. One of the core symptoms is weight gain.
So, what is happening to individuals with hypothyroidism which makes achieving weight loss harder?
Well, their metabolism is slowing down for sure, there is a decrease in thyroid hormones (T4 and T3), which is why it makes sense that other symptoms of having Hashimoto’s (the autoimmune thyroid condition) include constipation (slowing down of the digestive tract), slowed heart rate and poor circulation.
So what happens when you produce less thyroid hormones and your metabolism slows down?
Your BMR goes down. Hello energy balance again.
You perhaps move less as a result as one of the other main symptoms is fatigue.
Perhaps you exercise with less oomph because there’s just very little energy within you.
So in Mary’s case, instead of her BMR being 1289kcal and her eating less than 1639 calories thinking it was a calorie deficit, her BMR might be 1089kcal and so she actually needed to be a couple hundred calories lower.
Sorry thyroid people, when you zoom out, it is about calories in vs calories out.
Hypothesis #2 – I have high glucose/insulin levels
This one has been gathering traction as of late.
The idea goes like this, if I eat high carb/sugary foods and my insulin goes up, I’m going to be storing my calories and it’ll stop fat burning.
Furthermore, I’m also going to be sending myself on the proverbial ‘sugar rollercoaster’, where my appetite will massively increase when my blood sugar levels drop – leading me to eat more.
The sugar rollercoaster thing is laughable because there are studies to show that different carbohydrate sources (slow releasing carbs and rapidly absorbed carbs with different glycaemic responses) does not lead to more appetite (Peters et al, 2010).
I can see how the ‘insulin will make me store fat’ theory is easier to fall prey to, but has also been debunked. Read my article ‘Is insulin stopping you from losing fat’ here if you want to read more.
Finally, for those with PCOS and co-existing insulin resistance, the research currently suggests that about 50% of patients can have a lowered BMR by up to 40% (Georgopoulos et al, 2009).
Again, meaning that you’re likely not expending as many calories as you think you are and therefore need to lower your calorie intake for you to actually move into a deficit.
Energy balance again.
Hypothesis #3 – My cortisol is really high
This one is actually pretty nuanced, and big take home message #2 is:
Whilst insulin is the hormone responsible for bringing in calories to be stored or used, there are many opposing hormones that do the opposite thing.
Glucagon, adrenaline, noreadrenaline and cortisol all work to pull out stored calories to be used as energy when we need it.
Don’t believe me?
What’s the famous fight or flight example people often use?
Being chased by a sabre toothed tiger, right?
When your fight or flight system is activated, cortisol amongst other hormones are released to start mobilising stored energy (that insulin brought in), to help you run away.
So if anything, cortisol works in-line with weight loss.
The moment you eat, insulin is released to store calories away, but the moment you need to move (probably at higher intensities) cortisol is there to help give you that energy.
So what does this all boil back down to?
Energy balance.
Now, I know what you’re about to say.
But Danny, we have different types of stress now.
Our stressors aren’t physical in nature, more mental, psychological and emotional which doesn’t require movement, yet the response of producing cortisol is still the same.
What’s happening here? Two things.
1. There does seem to be some evidence that chronic cortisol exposure can have a fat ‘redistribution’ effect, where adipose tissue (fat) gets redistributed and stored abdominally (Van der valk et al, 2018).
Said another way, if you’re chronically stressed, not moving much, you could start seeing some fat build up around your mid-section.
But that doesn’t mean calories in vs calories out doesn’t work…
If you were truly in a calorie deficit, you would see weight/fat loss despite being highly stressed.
The problem is the following:
2. When people are stressed, they tend to eat more and move less. Don’t get me wrong, some people do turn away from food when stressed, that definitely does happen.
However, more often than not, people comfort themselves with highly calorific indulgences, whether that is food or alcohol which usually makes this still, an energy balance issue at the end of the day if it is leading you to eat more.
Hypothesis #4 – The calories within highly processed foods are different to whole
foods.
One common argument here being thrown around these days is that food items like nuts/almonds contain fewer calories available for us to absorb compared to how much it states on the package. (This is likely due to the calories wrapped up within the undigestible fibrous content of nuts itself).
I.e. let’s say for arguments sake 10g of almonds contain 100 calories, the suggestion is that because we can only absorb 70 of those 100 (I’m making up numbers here), then that makes calorie counting pointless.
The fact of the matter is, sure, there are flaws to calorie counting. There are blind spots to it that you won’t be seeing.
But again, just because it can be slightly inaccurate, does not make energy balance any less true than the fact that my pen will fall to the floor every single time I drop it.
Highly processed foods also causing a whirlwind of controversy these days.
The common argument here is that 100 calories of donuts cannot be the same as 100 calories of apples.
Final big take home message here is…
ALL calories are created equal. However, how these calories end up reacting within the body can be different.
Saying calories are created differently is like saying two cars have different miles per hour within them.
Or that two different tape measurers have different centimetres and metres to them.
Highly processed foods tend to have a lower thermic effect of food to them compared to whole foods, some research suggests by up to 50% (Barr & Wright, 2010).
Your thermic effect of food only covers about 10% of your total daily calories burned so it’s not a huge amount.
But, done repeatedly, this could stack up to make an impact on your weight loss efforts. Especially when you consider that these highly processed foods contain very little satiating components to them (protein & fibre) which makes them very easy to overeat.
Again, impacting energy balance.
To wrap up, there is one final idea to take away with you.
Energy balance is not static. It’s fluid and dynamic.
The calories you bring in can have an impact on your calories out.
The constitution of the calories within highly processed foods impacting your thermic effect of food is one good example.
But again, it only means that your ‘goal-post’ shifts a bit. Your perception of how to attain a calorie deficit is what needs refining.
The law of energy balance stays intact.
References
https://www.nature.com/articles/ejcn2010189#citeas
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5958156/
https://pubmed.ncbi.nlm.nih.gov/18678372/