CALORIE DEFICIT - WHAT IS IT AND HOW DO YOU CALCULATE IT?
BY PW NUTRITIONAL ADVISOR, JACK
We get a lot of questions here at Protein World from you guys about weight loss! It can be a confusing topic with so many weight loss myths and diets on the market! So today I’m going to try and explain with the only information you need to know about how to lose weight. You need to create a calorie deficit!
What is a calorie deficit?
A calorie deficit in its simplest terms is consuming less calories per day than you use. It’s literally that straightforward. But you probably already knew that! What you might not know is the importance of a calorie deficit for weight loss, and how to calculate and tailor one for yourself. This is going to shock some of you so make sure you’re sitting down… Ready? The only way to lose weight is to create a calorie deficit… I know, I know, you’ve read about and tried the hundreds of different diets out there and were convinced that the next one would be the one for you! The best way to lose weight, and keep it off, is to eat a diet that creates a calorie deficit which works for you and your current lifestyle, and that you can maintain for a sustained time period. If you can do this, I can personally guarantee that you will lose weight. So now you know a bit about calorie deficits, I can tell you how it works and how you can make it work for you.
How do you calculate your calorie deficit?
To work out how many calories you should be eating and therefore how much of a calorie deficit you need, there is some other information you need to know first. You need to know your total daily calorie expenditure and from there you can tailor your food intake to make a calorie deficit that suits you.
You use calories for everything you do during a day, from washing the dishes, walking up the stairs, to exercising in the gym, even breathing requires calories! There are three components of calorie expenditure which when combined will equal your total calorie expenditure across a day:
1. The largest percentage of your daily calorie expenditure is made up by your resting metabolic rate (RMR). This is the calories your body uses to perform basic actions to keep you alive such as breathing, circulating blood, and basic brain function. You can determine this number using your height, weight, sex and age. There are plenty of online calculators to work out your RMR from this information. Personally, I recommend this one >>> https://www.omnicalculator.com/fitness/bmr-harris-benedict-equation
2. The thermic effect of food, which is the calorie cost of processing food consumption, i.e. digestion, storage and excretion. It is equal to approximately 10% of your total daily calorie intake
3. Physical activity calorie expenditure, refers to all the calories you burn during the day doing any form of activity or exercise, including brushing your teeth, washing your hair, walking to the shops, or going for a run! This is calculated as a multiplier of RMR. You can place yourself into one of the following simplified categories based on your individual activity level using the following values:
- Sedentary (e.g. office-based job with no exercise) = RMR x 1.2
- Lightly active (e.g. office-based job with light exercise 3-5 times per week) = RMR x 1.5
- Moderately active (e.g. moderately labour-intensive job with light exercise 3-5 times per week) = RMR x 1.8
- Vigorously active (e.g. very labour-intensive job with moderate to vigorous exercise 3-5 times per week) = RMR x 2.2
Once you have calculated your total calorie expenditure, you can then tailor your dietary intake to create a calorie deficit.
Tips for creating a sustainable calorie deficit
Your calorie deficit should never be too extreme as this is unsustainable and any weight lost will likely be regained in the future. If that sounds familiar for you, it’s likely that you were making too drastic a change to your diet which didn’t suit you or your lifestyle. The lowest your calorie intake should ever go is equivalent to the value of your RMR. If your calorie intake goes lower than your RMR your body will struggle to perform all those basic functions I mentioned earlier, and it could cause health problems if you do so consistently.
A deficit of 500 calories per day, which is equivalent to 3500 calories per week, should result in 1 pound of weight loss per week. Exercise is not only a great way to improve your general health and wellbeing! It also provides an excellent method of creating a greater calorie deficit.
Let me give you an example of how to calculate your calorie expenditure and work out your calorie deficit:
A woman aged 35, weighing 75kg and being 160 cm tall will have an RMR of 1485 calories, i.e. this is how many calories she needs for all of her basic body functions. Therefore, I would not recommend that she consumes below this number of calories in a day.
She has an office-based job and goes to the gym three times per week so her physical activity multiplier is 1.4. 1485 x 1.4 = 2079 calories.
Plus, approximately 10% for her thermic effect of food which is 207 calories. Added to her RMR and physical activity expenditure this totals 2286 calories per day. This is her estimated total daily calorie expenditure.
If she wants to have sustainable weight loss of approximately 1.5 pounds per week she would need to create a calorie deficit of 750 calories per day from this value. 2286 – 750 = 1536 calories. This is therefore how many calories she should aim to consume per day in order to lose 1.5 lbs per week. She can then tailor her food intake to meet this calorie intake value.
So working out a calorie deficit for yourself may require a few calculations on your part, but knowing your calorie deficit will help you to better understand your weight loss, and support positive and sustained weight loss results.
If you are looking to lose weight with a structured routine, then The Slender Plan is a great place to start. Providing your breakfast, lunch and afternoon snack for Monday-Friday with a 70-page weight loss guide teaching you how to create balanced meals in the evenings and on weekends so that you can start to make a lifestyle change. The Slender Plan also contains a week of recipes with rough calorie guidelines to help you create a calorie deficit and start working towards your goals.
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