Calories – do they matter?


Is it that simple? Probs not, let’s be honest.

If you’ve done some reading around weight and weight loss you’ll find the space filled with conflict and opposing ideas. The great thing about the scientific method is that it suggests we should always challenge our own beliefs and biases. There are many different ways to get a job done and not all ways will work for or be palatable to all people.

The two main competing camps- Team CICO Calories in Calories out vs Team cals don’t matter.

It can’t be disputed that a calorie deficit is required for weight loss when we are aiming for fat loss and improving health(metabolic health in particular). However, the idea of calories in calories out as a hypothesis is mixed up with the strategy of calorie counting. They are not the same thing. The idea of creating a calorie deficit by any means necessary becomes a hammer rather than a more selective tool that’s required to view the science in this space.

The first law of thermodynamics – What does this even mean and why do people talk about it in relation to calories and weight loss?

This law says that the energy within a closed system is equal to the energy entering the system, minus the energy leaving a system. I’ve put it in because it’s referenced over and over as ‘ the answer’ – It’s science! they shout.

The first law of thermodynamics is obviously actual science! When it comes to nutrition it’s so complicated and nuanced, with so many caveats, in our opinion it’s hard to say the law is completely true for weight loss. It’s definitely VERY MISREPRESENTED.

So according to this law – the energy within us is equal to the energy we put in minus the energy we burn.

Energy stored in us (fat)  = Energy in MINUS Energy out 

Energy in = Food and Drink

Energy out ( TDEE)* = BMR** + thermic effect of food + PAE *** ( see below for definitions)

The CICO hypothesis suggests that

Our weight = Calories in – Calories out

Historically, because of this people have said that we gain weight because we have eaten more calories than we have burned. For the most purposes this is true, we can’t deny that. This has then me mixed up with calorie counting. We do not love calorie counting at Resilience Health

But it’s all just a bit more complicated than we are led to believe.

Calories out is affected by hormones, genetics, food quality, type of exercise, length of exercise, how long you sit for when you’re not exercising! It’s affected by your macros, your micros, your previous dieting history your muscle mass. You get the picture.

Let’s not get these things twisted CICO doesn’t = calorie counting. Also,CICO also doesn’t explain itself well or put itself across in a particularly understandable fashion on twitter!

We know that the calories IN part of the equation is related to factors that come way higher on the list than a lack of will power, laziness or a don’t care attitude.


The type of food, the nutrient density, the protein levels – the quality of the food counts.

The eat less and move more idea is not working for people. We live in an environment that bombards us with easy to access highly palatable foods. Navigating this takes some work!

Feeling hungry on a calorie restricted diet is miserable and unsustainable. The idea of weight loss itself needs a paradigm shift, we need to be thinking about fat loss, our lean muscle is super precious and super important, we certainly don’t want to be losing that. Satiety is queen, for sustainable fat loss.

Our muscles are a longevity organ. We need to look after them. Our cells need micronutrients to make hormones and neurotransmitters. Our mitochondria need more than empty calories.!

The food environment isn’t going to change any time soon. There are hundred of easy options that are nergy dense and nutrient poor. We need a framework that works for us that not only achieves fat loss, but works when we are in maintenance mode too . It needs to address the fact that even though you can lose weight by just eating the right amount of peanut butter and jam sandwiches for a prolonged period of time,you aren’t going to be anywhere near meeting your health needs, being able to regulate your appetite or protecting that muscle of yours.

*TDEE Total Daily energy expenditure

**BMR- Basal Metabolic rate -the energy required to keep the lights on- ie regulate our temperature, keep all metabolic processes going etc

***PAE- Physical activity expenditure which is a total of the energy used to just move and the exercise we decide to undertake, its made up of EAT AND NEAT — Exercise Activity Thermogenesis ( the training we do) and Non Exercise Activity Thermogenesis ( walking back to our car/ the kitchen, chasing the dog)

   Rolls, B.J., Dietary energy density: Applying behavioural science to weight management. Nutr Bull, 2017. 42(3): p. 246-253.

     Raynor, H.A. and M. Vadiveloo, Understanding the Relationship Between Food Variety, Food Intake, and Energy Balance. Curr Obes Rep, 2018. 7(1): p. 68-75.

“Food intake affects all the components of total daily energy expenditure – but predominantly diet-induced thermogenesis – with different effects according to the macronutrient composition of a meal and daily variation within the same individual”

-Bo et al. 2020

     Vadiveloo, M., H. Parker, and H. Raynor, Increasing low-energy-dense foods and decreasing high-energy-dense foods differently influence weight loss trial outcomes. Int J Obes (Lond), 2018. 42(3): p. 479-486.

A calorie is a calorie” violates the second law of thermodynamics