How Fast Can I Lose Fat?

Everyone wants fast results, so it is only natural that you would want to lose fat fast.

However, losing a significant amount of fat is not something you can do over a short time-span, e.g. two weeks.

Losing fat simply takes time. If you are expecting to see some of the exceptional results often advertised by the weight loss industry, then you will be disappointed.

If these claims are true at all, it is important to understand that the weight loss consist of other things than fat – i.e. water and muscle.

It is not possible to lose 20 pounds of fat in two weeks. And this is still true for most people even if no calories are consumed at all in the two weeks.

To make things even more frustrating, keeping track of fat loss can also be hard.

In this article, I will help you get a better understanding of fat loss and help you set realistic expectations, and of course help you answer the question: how fast can I lose fat.

The Basics of Fat Loss

Gaining fat or losing fat is essentially a question of energy balance. There are many factors that can come into play and make it very complicated to figure out, but it is still a matter of energy balance.

In order to lose fat, you need a deficit in the energy balance of your body – a calorie deficit.

The simple way of thinking calories in versus calories out provides an excellent guideline that predicts fat loss with a relatively small margin of error if certain requirements are met.

Of course, not all calories are created equal and we are ourselves incredibly complex biological creatures, so using this approach is not an exact science.

If you want to stay healthy both physically and mentally, maintain muscle mass and be able to function normally during your busy day you have to be smart with that calorie deficit.

The main thing is that you can’t go crazy with the deficit because then you will also lose muscle mass. You need to have what I like to call a “moderate calorie deficit” which for most people comes from eating 20 – 25 % fewer calories.

Additionally, I recommend low-volume weight training to ensure muscle retention and low-intensity cardio to increase energy expenditure without increasing appetite.

It is also recommendable that you increase protein intake since it helps ensure retention of muscle mass which should always be the main priority.

Regarding fat and carbs, I recommend that you make sure you get a good amount of both. Don’t go too low in either group, unless you are doing the ketogenic diet of course.

Determining Rate Of Fat Loss

In order to have a calorie deficit, you first need to understand and estimate your so-called maintenance calories and then subtract e.g. 20 – 25 %. Your maintenance calories are the number of calories you need to neither gain or lose weight.

A very simple yet for most people quite accurate way to estimate maintenance calories is this small equation:

Body weight x 15 (lbs) or body weight x 33 (kg).
This assumes about 60 minutes of physical activity.

With your deficit determined you can then calculate how fast you should lose fat based on how much energy is estimated to be held in your body fat.

In general, losing 1 pound of body fat should equate to a calorie deficit of approximately 3500 calories which is 7700 calories for a kg of body fat. This is an established and old rule that you perhaps have heard about before.

Normally 1 gram of fat accounts for 9 calories, but the reason why 1 kg of body fat is not 9000 calories is that human fat cells are estimated to be around 87 % fat.

how may calories in fat

Our body fat is not even 100 % fat.

All this being said, it is important to understand that you can’t directly control whether your body is burning only fat for energy.

However, there are things you can do to promote fat loss and maximize muscle retention. 1) It is very important to do heavy weight training and 2) I would recommend that you at least check out intermittent fasting.

How Fast Can I Realistically Lose Fat?

Here is an example that should make things easier to understand.

Ben’s maintenance calories are 75 x 33 = 2475. He has decided he wants to eat 25 % fewer calories, so his calorie intake should be 2475 x 75 % = 1856.25

This is a daily deficit of 2475 – 1856.25 = 618.75 calories and a weekly of 4331.25.

Ben also adds in additional low-intense cardio. 4 times a week he walks 60 minutes while listening to interesting audio books. For convenience let us say that he burns 200 calories in one session, so it is an additional 800 calories (with his body weight it should be more than 200 calories).

Ben’s weekly calorie deficit is now 4331.25 + 800 = 5131.25.

His weekly fat loss can then be estimated to 5131.25 / 3500 = 1.46 pounds, or 5131.25/ 7700 = 0.66 kg.

Safe Fat Loss Guidelines

If you follow the approach of being “smart” with both your calorie deficit and training, you can refer to the table below to get a good idea of what you can expect.

I have called it “safe” fat loss because this is the kind of fat loss you can expect if you also prioritize muscle retention which you always should!

how fast can I lose fat

The rate of fat loss drops as you get leaner because as your body fat levels drop so does your calorie deficit.

The numbers are actually based on the strength coach Andy Morgan’s many years of coaching experience. His website is a great resource that I can highly recommend.

Fat Loss and Scale Weight

The initial changes in your scale weight are going to be much larger than the rate of fat loss.

This is mostly due to water weight fluctuations and because the lower food volume that is being consumed.

Exceptional Fast Fat Loss

As you most likely can guess, your rate of fat loss is really about how big a calorie deficit.

Some people have taken this to an extreme and have had great results.

They do what is called a water fast, where they only drink water for a considerable time, e.g. a few weeks.

Obviously, this leads to a huge weight loss consisting of mostly fat but also muscle. Personally, I think it is very extreme and I cannot recommend it.

If you ever want to try a water fast your self, be sure to consult with a professional first. Doing a water fast can lead to many problems, and if not dealt with correctly these problems can in the worst case lead to death.

The Awesome Nutrition Guide

If you liked what you read, and want to know more about calories, nutrients and how you can determine how many calories and macros you should eat to lose fat and retain muscle mass while being as enjoyable as possible, then you should take a look at my free mini-book titled the Awesome Nutrition Guide. It also got an accompanying email course.

I wrote it for both men and women!

It is a complete diet guide to getting a fit body and includes how to lose unwanted body fat and build strength and muscle.

It also reveals the diet secret to achieving your fitness goals.

Get it all for free as a welcome bonus when you sign up for my email list.




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My name is Marcus, I am a lawyer (LL.M.) and the founder of this website. Besides sometimes doing lawyer stuff, I like to write about fitness and health and share what I have found “works” for people like YOU. If you want to know more about me and my vision for this website then you can click here.

4 comments… add one
  • Aaron Oct 6, 2017 @ 3:26

    Interesting read, this can be helpful for anyone looking to lose weight fast. However I also recommend boxing workouts for anyone looking to lose weight fast because there is a lot of cardio involved. Weight matters for fighters and if there’s any way to cut weight down while keeping mass it’s by following their workouts especially since there’s a lot of cardio involved. You say fewer calories will help to lose fat does this mean I won’t be able to eat certain things I once could?

    • Marcus Oct 7, 2017 @ 2:07

      Hey Aaron. Boxing workouts sounds like a lot of fun! 🙂 But for me, I think they would be too intense for me while losing fat. I get a big increase in appetite after doing intense cardio exercise.

      When you are consuming fewer calories, it is probably going to be more challenging to eat certain foods that are calorie dense. But that doesn’t mean you can’t eat them. You just have to find “room” within your macros and calories. I talk about this in my post on how to eat what you want and still lose weight.

      But for my top resource regarding this, you should check out my free mini-book

  • D Apr 4, 2018 @ 23:47

    Hi Marcus,
    I signed up to receive your Nutrition guide. I tried twice, surely entered good email address, but I have not received anything – neither in my inbox or in junk mail. Is this still valid? Thanks

    • Marcus Apr 5, 2018 @ 0:33

      Sure it is still valid 🙂 I am sorry to hear it is not working for you and thanks a lot for letting me know.

      You say you are just entering your email in the box right? Well, I checked my email software and it did catch your email so it should have sent the email.

      In the meantime, you can use this link to download it.

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