How To Lose Weight Part 1: Energy Expenditure

Before we begin I would like to say that I do not advocate this as "healthy". It can be done in a healthy way - but in order to do this, we need a greater understanding of macro and micronutrients as well as taking into account the multifaceted approach to health that is physical, mental and social wellbeing. However, if you follow this protocol I can guarantee you one thing - you will lose weight.

Dieting is a funny word.

Often, it fills people with the dread of slurping down spinach smoothies for 8-12 weeks in the hope of dropping a few pounds before a holiday or wedding. Or not eating any carbohydrates for 6 months and pulling your hair out as you go cold turkey on sugar, have crazy mood swings and lose all energy to do anything.

The problem with the word "diet" is that it implies that for some period fo time you will adjust your eating & decision-making habits before returning to normal once you've dropped the desired weight. Well, the problem lies in the approach.

Demonizing any foods or food groups like this for most of us simply isn't sustainable.

So for now, discount the word diet, instead, I just want you to think about how aware you are about your energy expenditure.

By energy expenditure I mean, how much energy are you giving your body, from food, and how much energy are you using, through living (your metabolism) and exercise.

When it comes to losing weight there are two main factors

  1. Calories

  2. Consistency

We're going to talk about both of these today and I'll run you through a step by step process of how you can lose weight, even when eating junk food alone, although I don't recommend that part.

There are different types of calories but for the purpose of this post let's just agree that food contains chemical energy that can be measured as calories to give us energy for a variety of things.

People often only associate calories with exercising but do recall that copious amounts of calories are used throughout the day (and night) to maintain and regenerate various human physiological processes; regenerating cells in your skin, hair, and the myelin sheaths of our neurons in our brains, for example.

At the end of the day the above statement, a calorie is a calorie, is true. And while I'll be the last person to advocate eating processed foods pumped full of sugar and chemicals - you CAN actually lose weight while eating junk food so long as you're in a calorie deficit. But more of that later...

Basal Metabolic Rate (BMR)

The number of calories you use or "burn" if you were just to lay in bed and allow the physiological processes outlined above to occur without raising a finger is known as your Basal Metabolic Rate (BMR). Let's say for me, a 24-year-old man, my BMR is 2550 kcal (calories). Well if I was to do nothing that day except lie in bed and consume 2550 calories in food then I would precisely match the energy demand of my body and not gain or lose any weight... just 24 hours of my life.

It's actually a little more complicated than that, as your metabolism is made up of more than just your BMR, but the above explanation is all you need to get started, a more in-depth explanation can help if you've initially seen weight loss results but then have hit a plateau. Fear not, we'll come back to it later.

Calorie Deficit

All you technically need to do to lose weight is to end your day in a calorie deficit - because if I'm 200 kcal shy of my 2550 kcal BMR then my body will then need to create 200 kcal of energy from somewhere; and it does this by using stored food energy, known to you and me, as fat.

(Approximately 22g of fat to make 200 kcal).

However in the above instance, I was just laying still - while most of us have active lives and will actually need calories to walk, run, cycle, swim and lift weights. So we have the challenge of figuring out how many calories we burn doing such activities.

Then, at the end of the day, our body will be in 1 of 3 scenarios:

  1. More calories in than out (weight gain)

  2. Calories in match calories out (stable bodyweight)

  3. More calories out than in (weight loss)

There are plenty of calorie calculators that can help you give a rough estimate for your BMR - everyone's different; sex, age, height, weight and a host of other factors can affect it.

Once you've established a figure you'll need to try and calculate the calories you burn through activity in the day. Luckily for us, nearly all phones and watches are integrated with step tracking and activity calculating metrics which make this fairly simple.

What you need to make sure you do then is eat less than you burn during the day.. and this is where it can get a bit trickier.


Above is my food diary (using My Fitness Pal) from Friday, January 17th, and as you can see - I actually had 240 kcal left once you subtracted my BMR and my exercise - which as we eluded to earlier equates to about 22g of fat. I'm not actually trying to lose weight, but my body will have needed to use energy stores (body fat) to make up the deficit I got myself in.

In order to be in any way accurate, you need to be weighing/measuring your food intake throughout the entire day, and this is much easier said than done.

Apps these days do try to be proactive in helping though, easily scanning bar codes on packets and giving huge amounts of metric options to make logging convenient. You can always save meals, such that, if you're a creature of habit and have the same breakfast daily, logging that is quicker than checking Instagram.

I find a very helpful tool to be a set of small electric scales, that you can easily put your plate or bowl on before you serve up your salmon, sweet potato and veggies.

If you think this is doable then its time to tackle the second pillar; consistency.


Herein lies the next challenge. You're feeling inspired, you weigh track and enter your food from Monday-Friday similar to how I've done above. It's not perfect - but you've left yourself in a small calorie deficit, of let's say, 100kcal a day (500 kcal total). This is a great start... and then the weekend comes around.

A drink here and a meal out there and before you know it your 500 kcal over for Saturday. Well, I'm sorry to say but that does cancel out all your hard work throughout the week and let me stress it's not hard to end in a surplus; especially when:

  • A pint of Peroni 235 kcal

  • A pina colada cocktail 318 kcal

  • A 12-inch pizza can be up to 1800 kcal

Now, consider that it's very common among females and smaller males to have a BMR of under 2000 kcal a day. So you can see how you'll quickly eat into that, pardon the pun, even when adding your steps and exercise calories ontop.

It's not just being in a calorie deficit now and again, but consistently being in one, that will promote the most effective weight loss.

We can do some maths and figure out exactly how much fat you'd lose if you were in a 100 kcal deficit for 8 weeks:

  • 100 kcal deficit a day for 8 weeks (including weekends)

  • That's 5600 kcal deficit over 8 weeks

  • One gram of fat is approximately 9 calories

  • That's 622g/0.6kg/1.4lbs of fat loss

Counting calories can be annoying at times especially in social situations. But that's not the point. The point is you WILL lose weight if you are in a consistently small calorie deficit.

Lose Fat NOT Weight (or Muscle)

Right, so I need to get something out of the way. DO NOT try and lose too much weight at once, not only will it not be sustainable but it's likey to be harder to do and unhealthy; and here's why.

As you lose weight your BMR needs to be adjusted and since I slightly oversimplified our model earlier here's a diagram showing what your metabolism (your entire energy expenditure) consists of:

  • BMR: Basal Metabolic Rate as we discussed earlier - the physiological processes that occur as you read this article. this accounts for around d 60-70% in most people.

  • NEAT: Non-Exercise Activity Thermogenesis is living. All the activity that comes expected in a day. Like walking upstairs, playing with your dog & even fidgeting at your desk. NEAT accounts for about 30% of energy expenditure but can vary with lifestyle factors.

  • EAT: Exercise Activity Thermogenesis is intentional exercise. Exercise selection has an effect on how many calories you're burning. Strength training burns slightly less while HIIT training can be the best bang for your buck (How to Burn Fat & Increase Fitness Effectively)

  • TEF: Thermic Effect of Food is the number of calories you burn digesting food. Even though TEF accounts for only 5-10%, it still factors into energy expenditure.

So as you lose weight your energy expenditure will change - therefore your BMR will decrease and most likely your TEF will decrease too. So it's important to do weekly check-ins of weight so figures can be adjusted to suit your new metabolism.

Anyway, back to the point at hand. If you put yourself in too much of a calorie deficit you'll be in danger of tempting the body to burn that oh so precious muscle for fuel as appose to the body fat we desire (especially if you aren't eating enough protein).

You may even tempt the body to stop performing non-vital physiological processes such as regenerating hair and nail cells.

Just trust me, putting yourself in a massive calorie deficit, it's a bad idea. See [1] a paper investigating the notorious Minnesota Starvation Experiment. Where participants were put on huge calorie deficits and lost crazy amounts of weight resulting in some terrible physiological and psychological damage.

So, a small but consistent calorie deficit will help you maintain as a functioning human while slowly burning fat, without any risk of muscle wastage (provided you eat enough protein) or negative physiological or psychological effects.


To try and cover all there is to energy expenditure and weight loss in one short post would be silly of me. So here are today's takeaways - try them for this week, and I'll bring you Part 2 next week with more information on how to do this in a healthy and sustainable manner:

  • Get an estimate of your Basal Metabolic Rate (BMR) and Exercise Activity Thermogenesis (EAT)

  • Eat fewer calories than the above (you NEED to have some form of tracking for this to be accurate )

  • Don't put yourself in a big calorie deficit (we'll talk about how much soon) but for today let's say no more than 10% of your energy expenditure maximum!

That's all. For now. Unique differences between us as individuals will affect certain things but if you're serious about losing weight the best thing you can do is to be aware of your calorie intake and your energy expenditure.


Mark Haub, who teaches nutrition at Kansas State University, lost 27 lbs (12.2kg) from only eating "twinkies and Doritos" in two months [2]. As I say, I'm not calling this healthy - but using calorie restriction and consistency - nearly anyone can lose weight.

I'll link to How To Lose Weight: Part 2 - once I've finished it.

Thanks for reading, any questions, please comment below or drop us an email.



[1] Tucker, T. (2007). The Great Starvation Experiment: Ancel Keys and the Men Who Starved for Science. Minneapolis: University of Minnesota Press.

[2] -

Health concerns?

There can be some medical conditions that can impact weight loss. The most prominent one being hypothyroidism. This is outside my scope of practice and all I’m allowed to say is: if you suspect this to be the case, i.e you read through this whole article, and everything is in order–go see a doctor and get your thyroid checked out.

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