Calorie Deficit: Everything you need to know

What is a calorie deficit

In simple terms, a calorie deficit is when you burn more calories, by maintaining bodily functions along with overall activity, than you consume, through your diet.

But, what actually happens when your body is in a calorie deficit? Well, imagine pouring 250ml of water into a glass, and then, throughout the day, removing 50 ml of water every few hours. Eventually, the glass would be empty.

But what if that glass had a water reserve placed beside it from which you could also remove water?

Pouring the water into the glass = Your calories in (diet)
Removing the water gradually from the glass = Your calories out (daily activity and bodily functions)
The water reserve = Your body fat

As best as we could describe by using simple household objects, this is why being in a calorie deficit is the key to fat loss.

Is it healthy?

Mostly yes.

Currently, the worldwide prevalence of obesity has almost tripled since 1975. This is rather alarming when the data shows that a whirlwind of life-threatening health conditions arise when suffering from obesity.

Heart disease, respiratory problems, high blood pressure, diabetes, and cancer are only a small handful of the conditions that are much more common in those who are overweight and obese.

By consistently reaching a calorie deficit, while partaking in an active lifestyle, one can reduce these risks on a monumental scale. Providing you are meeting your macro and micronutrient needs, bringing your body down to a healthy weight and body fat percentage is one of the best things you can do; and this is only possible by reaching a calorie deficit.

Of course, in cases of severe eating disorders and starvation, a calorie deficit is not healthy.

How to calculate calorie deficit

The first and most important step to take would be to find out roughly how many total daily calories you are burning, on average.

From there, you’ll be able to ascertain an understanding of just how much fuel your body needs to cover all your bases (overall activity and bodily functions) in order to maintain your current weight.

Then, you would need to create your deficit by deducting an amount of calories from that total daily calorie number.

Don’t worry, we’re here to guide you through every step of that journey.

How many calories do you burn a day

In order for you to know the total calories you burn in a single day, you’re going to have to learn two very important, yet incredibly simple, acronyms.


If you were to rest all day, without lifting even your little finger to change the TV channel, would you still burn calories?

The answer is yes.

Think about it, you breathe, you think, you regulate your body temperature, you produce hormones, you circulate blood, as well as perform thousands of other essential-to-life tasks without a single movement.

Your Basal Metabolic Rate (BMR) is the rate of energy expenditure (calories burned) while at complete rest performing the tasks necessary in keeping you alive.

A parked car with the engine running still requires fuel, right?

But what about when the car begins to drive, turn corners, reverse, and brake?

It will require more fuel.

Introducing: Total Daily Energy Expenditure (TDEE)!

Yes, you breathe, you circulate blood, you regulate your body temperature (all of which are included in your BMR), but what about your lifestyle which includes taking your morning shower, climbing into bed at night, and everything you actively do in between?

This is where you’ll end up with the total amount of calories needed to keep you going throughout the day; your TDEE.

Your TDEE is everything you need!

We’ve put together an easy-to-use calculator that will give you a pretty accurate reading of your total daily energy expenditure, check out the TDEE Calculator (coming soon).

Let’s put this into practice by diving further into the energy balance.

In a single day, if you were to eat 2,400 calories (energy in through food and drink) and you were to burn 2,600 calories (energy out through TDEE) where would your body find the additional 200 calories to cover the additional energy output?

Remember the ‘water reserve’ from earlier in this article?

Your body fat is that energy reserve, and this is predominantly where your body will find those additional 200 calories to cover the deficit.

Over time, your reserve will get smaller and smaller, becoming obvious both on the weighing scale and in other areas such as clothes feeling looser and body measurements.

It’s key to remember that you can increase your TDEE by exercising/moving more, however, it will naturally change over time depending on age, body fat percentage, and lean muscle mass. For this reason, it’s important to regularly check your TDEE every couple of months.

How much of a calorie deficit is needed

This always comes across as a difficult calculation to make.

If the deficit is too small, fat loss results may be slow and result in declining motivation to continue.

If the deficit is too big, the results come quickly, but can also result in uncomfortable levels of hunger and even potential malnutrition without enough micronutrient-dense foods.

What needs to be found is a healthy deficit that meets somewhere in the middle. Providing enough micronutrients and macronutrients for optimum health, while not enough calories to create the desired deficit for fat loss.

Unfortunately, there is no magic number. But we can get you somewhere close!

Ideally, for moderate weight loss, you should aim for a deficit of anything up to 500 calories. Unless working with extreme weight loss goals, a 500 calorie deficit should be all you need to make excellent progress.

A common assumption is that a 3,500 calorie deficit will allow about 1lb of weight loss per week. This has been proven accurate in plenty of studies, however, this is not always entirely correct. Weight loss is not a linear process, one week you may make incredible progress, one week you may make no visible progress at all.

The key is consistency.

Remember, as long as you maintain a calorie deficit, you will lose weight.

Related: Why am I not losing weight in a calorie deficit (coming soon)

How to create a calorie deficit

Think about it, a calorie deficit is reached by creating a void. A void that cannot be filled and must therefore be compensated mostly with stored body fat.

There two ways to create a calorie deficit:

  1. Through diet
  2. Through exercise

Of course, through your diet is most certainly the easiest way to create a calorie deficit, but a combination of both diet and exercise has been proven to be the most effective way to lose fat.

Long term, the exercise will help you build more muscle which will consequently require more energy to sustain at rest.

An increased metabolism and some muscle at the same time? Who wouldn’t want that!

At Hit My Macros, our macro meal planner calculates your ideal nutritional targets to build the perfect, personalised meal plans that ensure you reach your physique and body-weight goals in no time.

Our workout planner will cover your training calendar too. Whether you’re a total beginner working out from home, or a veteran training at muscle beach, we have the right workout plan for you.

Does it matter what you eat

This is the perfect time to bring up:

The Twinkie Diet

In 2010, Mark Hubb, a professor of human nutrition at Kansas University, followed what he called ‘a convenience store diet’.

His premise?

‘That in weight loss, pure calorie counting is what matters most – not the nutritional value of the food’

After 2 months of a diet consisting mostly of Twinkies, Doritos, and sugary cereals, Mark lost 27lbs.

His body fat also dropped from 33% to 25%.

The key piece of information is that Mark held a calorie deficit (around 1,800 total calories consumed per day) for the entire time he was following the convenience store diet.

Was the diet healthy? No. With an abundance of refined sugar and huge lack of micronutrients, this is not something anyone should try at home.

But the point is the calorie deficit.

A calorie deficit will help you lose weight but it’s also important (even essential for survival) to consider the overall nutrition of what you are eating.

Eating high satiety, high-fibre foods (that stop you feeling so hungry) will help keep you on track with your diet, while aiding your digestion.

An added focus on eating high-protein foods can help maintain your muscle mass while keeping you feeling fuller for longer. Protein also requires the most energy to digest; around 20-30% of the total calories in protein eaten are used to digest it, which will in turn enhance your rate of fat loss.

Eating micronutrient dense food ensures your body won’t reach a point of malnourishment which will help keep your body healthy and performing at its best for the long term.

Example calorie deficit meal plan

What does a calorie deficit look like? That’s easy, using our meal planner, we can show you!

For a moderately active 170-lb man following a 2,000 calorie diet; his meal plan would look like this:
EDIT: Coming soon (you can generate a plan for free using our meal planner)

For a moderately active 140-lb woman following a 1,600 calorie diet; her meal plan would look like this:
EDIT: Coming soon (you can generate a plan for free using our meal planner)

Our meal planner calculates custom nutrition targets and creates personalised meal plans automatically, check it out! It comes with a trial period and no credit card is required on sign up.

>>>Create My Meal Plan<<<

Do I need to track calories?

Keep in mind, it is possible to consistently remain in a calorie deficit without counting calories!

Below, you’ll find a short list of some simple methods for reaching a calorie deficit without counting calories:

  • Use a smaller plate when serving your main meals
  • Use the 2:1:1 method for plate portioning: 2 portions of carbs in the form of vegetables and whole grains, 1 portion of lean protein, and 1 portion of healthy fat
  • Skipping deserts during the week – usually, a high-amount of hidden calories are found lurking in those little sweet treats
  • Aim for lower-calorie yet filling foods such as fish, chicken breast, eggs, tofu, vegetables, and berries
  • Drink more water – the difference between an unnecessary snack and waiting until your next main meal could come down to a glass of water or a cup of herbal tea
  • Walk more – roughly 500 calories are required to walk 10,000 steps. It may sound like a lot of walking, but throughout the day, it’s pretty quick to add up! Park a little further from work, and take the stairs more often – you’ll hit that 10k mark in no time

Can you build muscle in a calorie deficit?

This often falls within a grey area of fitness and nutrition, a grey area that we cover a lot more deeply in our Body Recomposition article (coming soon).

However, for beginners to weight training and exercise in general, it is possible to lose fat and gain muscle at the same time, and in many cases will achieve this by implementing a slight to moderate calorie deficit.

For those who are more intermediate to experienced in the realm of weight training, it comes down to preventing or heavily limiting any loss of muscle mass while achieving a calorie deficit.

For both examples mentioned above, a high protein diet while performing progressive, regular weight-bearing exercises is key in prioritising the loss of body fat over muscle mass.

When to stop a calorie deficit

Once you’ve reached your fat-loss goal, or even after making a vast amount of progress, it’s nice to take a break and reflect on both all you have achieved as well as what you have in mind for the future.

A great place to start is to understand your maintenance amount of calories.

What amount of calories allows you to fully fuel your workouts and daily activity, while maintaining a lower, sustainable amount of body fat?

You’ll find that over time, due to muscle gain, an increase in activity, and a revved up metabolism, you may need to readjust your calorie intake.

It’s also important to not completely sacrifice the cheeky treats that make the weekend extra special (don’t worry, we take those cheeky treat additions into account in our meal plan generator).

Ultimately, your diet (like life) is all about variety, balance, and moderation. Finding that nutrition sweet spot that allows you to maintain a healthy, active lifestyle; without monotony and boredom is the catalyst in helping you reach your goals, and excel past them.

For a fitter, stronger,
healthier you.

Calculate your macro and calorie targets, generate a meal plan you'll love, and level-up with structured workout plans.