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The fitness industry loves to promote this thing called a calorie deficit but what actually is that...

Calories are your body's fuel source so whenever you eat or drink anything that has a calorie in it you are providing your body with energy for its daily movement needs.

If you are highly active you will require increased calories while if you live a sedentary lifestyle you will not need as many calories in your day. Simple right? But how do you determine how many calories you actually need?

Let us break down the energy balance equation so you understand how this process works...

Energy Balance

Energy balance is the difference between total daily energy expenditure (TDEE) - energy or calories in.

How does your body utilise energy

Basal Metabolic Rate (BMR)

This makes up approximately 70% of your daily energy use and is basically made up of the calories you burn even if you did nothing that day. E.g. if you were completely sedentary you will only burn BMR that day!

Non Exercise Activity Thermogenesis (NEAT)

This makes up approximately 15% of your daily energy use and is made up of the things you do during the day without any mental input. Anything that does not include; sleeping, planned exercise/activity, and/or eating. Making an effort to change the way you move everyday will promote higher use of NEAT which burns more calories overall compared to exercise.

Thermic Effect Of Food (TEF)

This involves the process of eating and the process of digestion which burns calories or uses energy. This makes up 10% of your daily energy use which makes a significant impact upon your total daily energy use.

Exercise Activity Thermogenesis (EAT)

This is the process that most people think burns the most energy and makes the biggest impact on their total energy use. However it only makes up 5% of your total energy use... This makes the smallest dent in your total energy expenditure throughout the day and should not be looked at as the process that helps you lose weight or fat quick!

Now comes the next part of the process, what are you putting into your body that is resulting in the process of energy use by the factors listed above?

Calories In

Everything that you eat or consume that holds a caloric value will provide your body with energy. For survival you only need to fulfil on average your BMR or the 60% of your total energy needs. But as I said it is for survival you want to thrive and be full of energy everyday right?

So you ideally want to eat at maintenance for this meaning you are completely equal. Your energy in is = your energy out. 100% on both ends of the equation.

To do this you have to work out how many calories your burn during a full day and eat the amount that would balance this out.

There are many ways you can raise the amount you burn during the day by thinking about how your body uses energy. One of my favourite ways is increasing your daily activity levels with unplanned activity. Parking further away from the train station, taking the stairs rather the elevator, increasing your step count. These all add to your NEAT.

Calorie Deficit

Being in a calorie deficit means you are eating less than how much you burn in a day so you will ultimately lose weight if you continue this over time. If you are in a heavy calorie deficit or what I like to say more than 500+ calories you will begin to notice decreased energy levels, you may feel lethargic and you will not feel as good as you normally would. This is your body trying to tell you it needs more energy! Basically what will happen is your body will indirectly begin to decrease its daily energy use by showing signs of fatigue and forcing you to take extended periods of rest, you will have increased hunger levels in an attempt to force increased energy in and you will exercise less.

If your goal is to lose weight you have to battle through this however you can make it easier on yourself if you decrease the deficit that you are on.

Calorie Surplus

A calorie surplus is the opposite side which is signified by increased energy in compared to the energy out. Ultimately you will be getting more energy in than the energy you use in a day. If over time you are continuously in a calorie surplus you will be gaining weight as you have more energy than you are using over time which will be stored as fat.

The greatest benefit of a calorie surplus is your body loves it! You will be always full of energy and able to do a lot more than you normally would (within reason). You will not be feeling lethargic or tired, you will not be feeling this constant hunger and instead be able to push through and complete your daily tasks or activities a lot easier!

However the drawback is you will be storing fat increasing your fat storage over time...

Key Takeaway

So who is the winner? If you are happy with your current body composition my recommendation is to go straight into a maintenance or creating a balance between calories in and calories out. This means you will be balanced and have the energy you need for your daily expenditure needs and wants!

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