---
title: 'How To Calculate A Calorie Deficit For Weight Loss | Nutritionist Explains | Myprotein'
source: 'https://youtube.com/watch?v=ZGTMUwEDBu4'
video_id: 'ZGTMUwEDBu4'
date: 2026-06-30
duration_sec: 420
---

# How To Calculate A Calorie Deficit For Weight Loss | Nutritionist Explains | Myprotein

> Source: [How To Calculate A Calorie Deficit For Weight Loss | Nutritionist Explains | Myprotein](https://youtube.com/watch?v=ZGTMUwEDBu4)

## Summary

This video explains what a calorie deficit is, why it's essential for weight loss, and how to calculate one. It also discusses why knowing how to calculate a deficit isn't enough on its own and emphasizes the importance of monitoring progress and adjusting over time.

### Key Points

- **Calorie Deficit Definition** [00:33] — Every diet that helps people lose body fat works by helping you eat fewer calories than you burn.
- **How Different Diets Work** [01:23] — Keto, vegan, and low-fat diets all work by restricting certain foods to reduce calorie intake.
- **Calculating Maintenance Calories** [02:03] — Calculate maintenance calories by multiplying BMR (e.g., Harris-Benedict equation) by an activity factor.
- **Activity Factor Inaccuracy** [02:49] — Activity factors are notoriously inaccurate; you'll need to adjust later anyway.
- **Best Way to Find Your Deficit** [03:49] — The best way to find your deficit is to track food intake and body weight, then reduce calories until weight drops.
- **Measuring Progress** [04:49] — Weigh yourself daily and use a weekly average for a better measure of progress.
- **Weight Loss Plateaus** [05:04] — Weight loss slows because your body needs less energy and metabolism adapts; you may need to drop calories further.
- **Recommended Deficit Range** [06:04] — A deficit of 200-500 calories below TDEE is recommended; slower loss helps maintain muscle and is easier to sustain.

## Transcript

You just need a calorie deficit made, well true, it's also one of the most reductive things you can tell someone who's trying to lose body fat. That said, understanding how to calculate one is useful. So let's talk about that. How's it going guys? My name is Richie Kerwin and
today we're going to talk about what a calorie deficit is, why it's important for weight loss, and also why knowing how to calculate one isn't all that helpful on its own. Let's get started. Every single diet that has helped people to lose body fat in the history of humankind works on
the exact same principle. By helping you eat fewer calories than your burn. This is what's known as a calorie deficit. So if you eat 2,000 calories a day and your weight stays the same, that means you're burning 2,000 calories too. That's calorie balance. On the other hand, if you eat only 1,500 calories
and you keep burning 2,000 calories a day, that means you're in a 500 calorie deficit and will start losing weight. While you can technically increase how many calories you burn with exercise, this isn't effective long term. As your body adjusts to the extra exercise by reducing how much it
burns in other ways. While that happens, it's a topic for another video. That means that the most effective way to get into a calorie deficit is to control the amount of food and therefore calories that you eat. And there are many different ways to do that. So even if the diet seemed very
different, the principle is always the same. Keto diet work because fewer carbohydrates mean fewer calories. Vegan diets work because fewer animal products mean fewer calories. Low fat diets work
because low fat means fewer calories. The principle is exactly the same. Restrict the food or food group to reduce calories and lose weight. But you're better than some restrictive diet because you're
watching this video and now you know the principle of fat loss and don't have to try some stupid diet just to lose weight. You're welcome to dance. So how do you actually figure out how much to eat in order to lose body fat? I'm going to talk about two methods today. Firstly, you can calculate your maintenance
calories. That's how many calories you need to maintain your body weight. You do this by knowing your basal metabolic rate and multiplying it by an activity factor. For your basal metabolic rate or BMR
there are a lot of formulas available and one that I really like to use is the Harris Benetic equation which looks a little like this. Just enter in your details for weight, age and height and it'll give you your BMR. Once you have that you need to multiply it by an activity factor. This accounts for
the added energy that you burn by being active. Typically for someone who doesn't walk much and has a desk job and activity factor of 1.1 or 1.2 is okay. If someone is moderately active with exercise a few days a week and walks a little bit more an activity factor of 1.3 to 1.6 might be okay. Or for
someone with an active job like manual labor and a lot of exercise daily an activity factor of 1.7 to even 2 plus could be useful. Activity factors are notoriously inaccurate so don't worry about picking the right one. You'll need to adjust later anyway. So once you pick an activity multiplier
multiply it by your BMR and that will give you a rough idea of your total daily energy expenditure or TDEE. Alternatively you can search for a calorie calculator online put your details in there
and I'll calculate your calories for you. You can check out the my protein calorie calculator by clicking on the link in the description below. Now you may think that I haven't given a very detailed description of how to calculate calories and the reason is after working with hundreds of clients
with different body composition goals I know for a fact that calculating their energy expenditure with a formula just isn't that important. Here's the thing you probably don't even need to use a calorie calculator because they're just estimations of what you should eat. The best way to calculate
your calories is to actually monitor your body weight and track your calories and just reduce your calories a little until your weight starts to go down. That way is far better than any online calculator that helps you adjust your calories over time. Once you know how many calories you burn to maintain
weight if you want to lose weight you need to eat fewer calories than that. Now the only way you can eat less is by knowing how much you're eating at the moment. Now again you can do that in two ways. You can use a calorie or macro tracker literally any of them is fine and use that to eat fewer calories
or you can just keep a rough food diary of what you eat daily and just reduce your portion sizes. The advantage of the calorie tracker is it gives you details on macronutrients like protein, carbs and fats which we'll talk about in a moment. You'll also need to measure your progress and the
easiest way to do that is by weighing yourself daily. Without monitoring your progress you have no idea if what you're doing with your diet is working. There are plenty of other ways to measure your progress taking measurements around your hips and waist or taking progress photos but the scale is
probably the easiest. I'm not saying it's the best but it's the easiest. I say measure daily because your scale weight can change a lot from day to day. So if you measure daily and then get a weekly average that's probably a much better measure of your progress. One thing to bear in mind when you're
in a calorie deficit is that your weight loss will eventually slow down and stop. Even if you're still eating what was a calorie deficit for you before. This is totally normal and happens because when you
lose weight well later bodies need less energy and there's also some metabolic adaptation to dieting. This just means that your metabolism slows down a little to compensate for the reduced calories. The only thing you can do at this point is drop calories further to get back into a deficit
again. It sucks but that's just the way metabolism works. Now I haven't said how much you should drop your calories by because that depends on how fast you want to lose weight. If you have a bigger calorie deficit you lose weight faster and while some people like that because it can help keep them motivated
personally I think a slower rate of weight loss is a little bit better. It's easier to manage because you're not dropping your calories crazy low. For some people a hard deficit or a big deficit is easy to get sick of. Leave them to give up and end up robbing a bakery. Slow or weight loss will help you
maintain more muscle mass too. So depending on how fast you want to lose weight you could consider a deficit of 200 to 500 calories. That means 200 to 500 calories below your total daily energy expenditure.
Now the principle of weight loss is very simple but putting it all into practice is not easy at all. Especially when we haven't even spoken about other factors like protein, fats and carbs or motivation from dieting have a change and just by losing weight is so hard. These are all really
important topics and I've spoken about them before in previous videos so please check those out. So what do you think? Do you think you know how to work out a calorie deficit? As always if you have any questions let me know in the comments below and remember to like and subscribe to my protein
YouTube channel for more great evidence-based nutrition information.