Are all calories created equal?

What is a calorie? 

A calorie isn’t a physical substance like water or juice. But, just like centimetres and litres, a calorie is a unit of measure. More specifically, it is the amount of energy required to raise the temperature of one mL of water by one degree Celsius. The total amount of calories found in food is measured via a bomb calorimeter. This device measures the heat of a fuel sample when burned under stable temperature conditions to evaluate the calorie value. So technically, you could put wood in a bomb calorimeter and receive a ‘calorie’ value. The limitation is that humans can’t absorb calories and nutrients from wood (obviously), so many argue that calorie tracking isn’t an efficient means to lose fat because ‘not all calories are created equal’. 

The Calorie has been used to describe the energy content of food for hundreds of years. Likewise, the energy cost of exercise has also been measured via calories. If you’re not new here, you’ll know that Mark (and I) have repeated time again that to lose fat, you need to burn more calories than your body needs. And if you don’t believe us, then believe the law of thermodynamics, which states that energy can neither be created nor destroyed – only converted from one form of energy to another.

But is it fair to say that not all calories are created equal? 

A calorie is a calorie is a calorie, at least from a thermodynamic standpoint. Why? Because a calorie is a unit of measure. 

Now, does that mean that we all absorb the same amount of energy from foods? 


A great example of this is found in the almond. Due to almonds’ natural cellular structure, we may absorb fewer calories than is displayed on the label. Another example is in resistant starch and insoluble fibre. Studies have shown that energy absorbed from these foods varies among individuals.

So, does that mean that energy balance is a lie? 


The amount of energy that we truly absorb from food is questionable. You only have to look at a person with uncontrolled Crohns disease or a coeliac who is eating gluten to realise that food absorption is not simple. But no one (at least those who understand science) is questioning that a bomb calorimeter indicates that if x = y calories, then you will absorb z calories. No, calories are simply the unit of measure. Energy balance is the difference between the energy you absorb and the energy you burn. Whether you absorb 100% of the calories found in almonds or 70%, you are eating (absorbing) your maintenance calories if you maintain your weight. If you lose fat, you are eating (absorbing) fewer calories than you burn. And if you are gaining fat, you are eating (absorbing) more calories than your body burns. 

So, what happens when we eat calories? Where do they go?

I will skip a few steps otherwise, this will turn into a novel. For simplicity, let’s say that your food isn’t ‘inside’ your body until it passes your intestinal lining. Meaning that the calories derived from food aren’t absorbed by your body until then. But once the food is inside your body, you will do one of three things with it: 

  1. Use it
  2. Get rid of it
  3. Store it

How do we use it? 

Your body will use glucose and fatty acids to produce adenosine triphosphate (ATP), which is your body’s primary energy source. What isn’t converted to ATP will be converted to carbon dioxide and water. Now, amino acids can also be used to produce ATP (amino acids do many crazy and beautiful things, but I won’t go into that here). ATP is required to make your body function and is used up in this process. Then, suppose you have a shortage of a specific macronutrient (because they all play an essential role). Your body will synthesize them via processes like gluconeogenesis (to create glucose) and de novo lipogenesis (to produce fatty acids and protein). 

 How do we store it? 

Simply put: 

  • Amino acids are used to build or repair proteins.
  • Glucose is stored as glycogen.
  • Free fatty acids will be packaged into triglycerides and transported to your muscles and fat cells (this is how we gain fat) to be stored intracellularly or extracellularly.

How do we get rid of it? 

This is in the context of losing fat. Have you ever stopped to wonder what happens to that fat we lose? Does it just disappear? If we go back to the law of thermodynamics (energy cannot be used or destroyed), then the simple answer is no. So what happens to lost fat? It’s breathed out as CO2 or urine – pretty cool, right? 

Yours in health,

Sheridan Skye

Head of Nutrition


5 Reasons you are not losing fat in a deficit

Let us start this by being direct – if you’re not losing fat, you aren’t in a deficit. I know! The most unhelpful answer ever. Nonetheless, it’s true. If you are familiar with Mark’s methods, you will know that to lose fat, you need to consume less energy than you burn each day. It’s the law of thermodynamics, and we can’t get around it (I’ve tried many times). So let’s look at why someone might think they are in a deficit but, in reality, aren’t and what you can do to fix it. 

Reason One: You are consistent during the week, and then you go ‘yolo’ on the weekend. 

You decide that you would like to lose some fat. Monday rolls around, and you are motivated as hell! This time will be different. You meal prep and schedule your workouts for the week. You finished Monday and Tuesday strong, Wednesday was a little hard, but you pushed through. Then Thursday rolled around, and you didn’t plan your day, so dinner ended up being something you threw together (it was too hard to track, though, so we will assume it was within your calories). Then Friday rolls around, you are out of groceries, and the girls hound you to go out for a few drinks. You oblige and promise it will just be one drink. Seven drinks later and a 4 am stop in at McDonald’s for a sneaky cheeseburger. Your mind decides that your diet is ruined anyway, so you’ll start again on Monday. So you keep yoloing it. But here’s the catch, calories count on weekends just as much as they count during the week and it isn’t all that hard to take yourself out of a deficit or even put yourself in a surplus with a few untracked or yolo days of eating. Your net caloric intake needs to be less than your net energy expenditure to lose fat. 

The remedy: Be consistent throughout the entire week. Set yourself realistic goals. You don’t have to give up your social life or become a hermit if you want to lose fat. Instead, consider calorie cycling or choose to have one maintenance day per week. 

Reason Two: Your tracking is inaccurate. 

Tracking is a skill that takes some practice to become proficient in. Most people are familiar with My Fitness Pal, the database widely used to track calorie and macronutrient intake. The problem with My Fitness Pal is that anyone, yes anyone, can input entries onto the platform, leaving each entry with a large margin of error. Even the ‘verified’ options aren’t always accurate. 

You might also run into trouble if you weigh things cooked but track them raw or vice versa. This is because the cooking process can retain or lose fluid which changes the weight of the food but not the calorie or macronutrient breakdown. For example, if you start with 150g of raw chicken breast and weigh it afterwards, it will weigh less (chicken loses water during cooking). It now weighs 90 grams, and you track it as ‘chicken breast, 90g raw’ – you are effectively missing 60g from the amount you actually consumed and therefore, you have consumed more calories than you thought. 

The remedy: Use the NUTTAB database to log anything that doesn’t contain a label (meat and produce). You can do this by searching ‘chicken breast nuttab’ on My Fitness Pal. Ensure you scan the barcode of packaged items and check them against the label. Finally, decide whether to track your food cooked or raw (raw is more accurate, but that is an entire discussion that we won’t go into here). Be consistent with that method of tracking to decrease marginal errors. 

Reason Three: You don’t track licks, bites or sips. 

I’m a Mum, so I am notorious for this if I’m not mindful. But, let me tell you, the bites, licks and sips you take throughout the day add up! Especially when it’s from foods with a high-calorie content per 100g (hello, peanut butter). So, if you’re going to track, track everything – even the bites, licks, and sips. 

The remedy: minimise mindless snacking. Snacking isn’t ‘bad’ when it is intentional, but unconscious snacking brings many people undone. 

Reason Four: You have overestimated your TDEE.

A TDEE calculator provides a ballpark figure at best. It does not account for your own unique metabolic needs (thyroid hormones, mitochondrial efficiency, NEAT levels etc), yet people become very dogmatic about finding the perfect TDEE calculator. It doesn’t exist (well, it does, but it’s an expensive process called indirect calorimetry). So, keep this in mind when using a TDEE calculator. 

The remedy: use a TDEE calculator to determine a ballpark figure of where you sit. Then become somewhat of a detective. How is your body responding after a few weeks on those calories? (don’t change things sooner than 2-3 weeks, be patient). Is your average weight trending down? Are your measurements going down? If yes, great! Don’t change what’s not broken. If not? Your actual TDEE may be lower than the calculator predicted (assuming you have been consistent with your calorie intake). 

Reason Five: You have overestimated your daily activity levels. 

Most people grossly underestimate their daily calorie intake and overestimate how active they are. 

The remedy: when choosing your daily activity level, move away from trying to determine how many calories you burn during your training. Resistance training burns less overall calories than you think. Instead, think about how active you are throughout the entire day. Are you a nurse? Or do you work in administration? Are you a chef? Or are you a web developer? Your occupation and general lifestyle have the most significant impact on how active you are throughout the day. So, if you’re a nurse, you will probably sit a little higher than someone who works in administration. When in doubt, underestimate. 

Yours in health,

Sheridan Skye
Head of Nutrition