You already know that in order to lose body fat you must be in a calorie deficit, right?

But, is there actually an optimal calorie deficit for fat loss? And if so, what does it look like?

Is there an optimal calorie deficit for fat loss? Yes, there’s an optimal calorie deficit for fat loss. To lose body fat at any noticeable speed while preserving your muscle mass in the process, the size of your calorie deficit should be based on your body fat percentage. The higher your body fat percentage the quicker you can lose fat and vice versa.

In this post we’ll explore the concept of setting up your calorie deficit based on your body fat percentage more in depth. We’ll also look at an incredibly effective strategy for reducing your calorie deficit as your body fat percentage comes down over time.

Let’s go!

Why You Should Set up an Optimal Calorie Deficit

When it comes to getting lean and muscular, i.e. a ripped physique. You must make sure you lose fat and not muscle when you’re dieting for fat loss.

Because if you lose a bunch of muscle mass, then you’ll just end up looking skinny, or even skinny fat once your cut is over.

And even though it’s true that you must eat enough protein and also strength train in order to keep your gains during a cut. These factors are still not the most important ones if you want to preserve muscle mass on a cut.

What’s most important is your rate of weight loss.

You see, calorie balance always take precedence above everything else when it comes to changing your physique, as demonstrated in this pyramid (which btw is completely science based):

As you can see, calorie balance are at the bottom of the pyramid, which means it’s the most important factor when dieting to lose fat. Then, at second place you have your macros and strength training which shares the same tier.

And this makes the first part of why you want to set up an optimal calorie deficit.

The second part is to make sure you lose fat as quickly as possible, while still managing to preserve muscle mass.

Because truth is:

Being in a calorie deficit sucks. It’s much better and more enjoyable to be over with it as quickly as possible, so that you can rock an awesome and aesthetic physique sooner rather than later. And/or go back to making gains again, this time at a lower body fat percentage.

So, let’s look at…

How to Set Up an Optimal Calorie Deficit for Fat Loss

In order to lose fat quickly and effectively while preserving all your hard earned muscle mass, your calorie deficit should be set up accordingly to your body fat percentage.

And here’s how you do that:

Step 1. Estimate Your Body Fat Percentage

Finding out your body fat percentage dead on is hard, if not impossible to do without dying and ending up at the morgue.

Not even the best body fat percentage tools in the world, such as; DEXA scans, Bod Pods, and Calipers etc. can pull it of 100 %.

Luckily though, in order to set up an optimal caloric deficit for fat loss, you only need to be within a certain range. And that’s why it’s enough to get an estimation only.

Fortunately, there’s one tool that can do this easily and conveniently. It’s also surprisingly accurate for most people, with a standard error deviation of only +/- 3%.

It’s named the US Navy body fat percentage formula, and here’s a link to it (opens in a new window):

The Iron Built Fitness Body Fat Percentage Calculator

Now, the drawback of this formula is that it doesn’t work well for all people.

Individuals who genetically store more fat on their legs and arms will get an estimation that’s way lower than what their body fat percentage actually are.

So, if you know that you store most of your fat in these places, then the next best method to estimate your body fat percentage with, would be by comparison pictures.

All body fat percentages has somewhat of a certain look to them. Sure it might be a few percentages off. But as I just mentioned, all you need to find out is the range you’re in.

Here’s a great picture by BuiltLean displaying the different body fat percentages you can use to compare yourself with, in order to get an idea of the range you’re in.

Step 2. Set Up Your Calorie Deficit Based on Your Body Fat Percentage

Now that you know which body fat percentage range you’re in, it’s time to set up your calorie deficit based on that range.

There’s a theoretical limit to how much fat that can be released from the fat stores in a single day, where any additional weight lost above this limit will be muscle mass, no matter how high the protein intake is.

This limit is inversely proportional to how lean we are, meaning that the leaner we get, the smaller the deficit must be to ensure muscle retention.

Now, smarter people than me, like trainer and blogger Andy Morgan, have experienced by working with hundreds of clients that the optimal rate of weight loss should not be based on body weight, but on the following body fat percentage ranges:

Optimal rate of fat loss men

Body Fat % Fat Loss/Week 30%> 20-30% 15-20% 12-15% 9-12% 7-9% <7% ~1.1 kg (2.4 lbs) ~0.9 kg (2 lbs) 0.45-0.7 kg (1-1.5 lbs) 0.45-0.6 kg (1-1.3 lbs) 0.35-0.45 kg (0.75-1 lbs) 0.2-0.35 kg (0.45-0.75 lbs) ~0.2 kg (0.45 lbs)

Optimal rate of fat loss women

Body Fat % Fat Loss/Week 40%> 30-40% 25-30% 22-25% 19-22% 17-19% <17% ~1.1 kg (2.4 lbs) ~0.9 kg (2 lbs) 0.45-0.7 kg (1-1.5 lbs) 0.45-0.6 kg (1-1.3 lbs) 0.35-0.45 kg (0.75-1 lbs) 0.2-0.35 kg (0.45-0.75 lbs) ~0.2 kg (0.45 lbs)

So, let’s say that you’ve estimated yourself to be somewhere in the 15-20 % body fat range. This means you can potentially lose 0.45-0.7 kg (1-1.5 lbs) per week without risking muscle loss.

And exactly which rate of weight loss you choose should first and foremost be determined by what you think you’ll adhere best to. Losing 0.7 kg will be tougher than losing 0.45 kg per week.

Secondly, if you’re closer to 20 % body fat then you’d be more safe aiming for the higher number, both when it comes to muscle retention and adherence. And vice versa if you believe you’re closer to 15 %

So, for this example, let’s say you choose to go with a number dead in the middle, which would be 0.6 kg per week.

Here’s how to set the deficit:

1. Find your maintenance calories (TDEE)

Here’s a simple maintenance calories formula that works exceptionally well:

Body Weight in pounds x 14-17 = Estimated Daily Calorie Maintenance Level

Body Weight in kilos x 31-37 = Estimated Daily Calorie Maintenance Level

You decide which number in the range you use to multiply with accordingly to your daily activity.

If you’re mostly sedentary throughout your days, use the lower number. And if you’re very active throughout your days, use the higher number. If you’re moderately active, pick a number in between.

This will just be a preliminary number, and it doesn’t need to be perfect, you will most likely have to adjust your caloric intake later anyways.

Note: Ideally you would want to take a week where you track all your food and weigh yourself daily to learn exactly where your maintenance calories are at.

Let’s say for this example that your maintenance calories are 2800 per day.

2. Calculate your calorie deficit numbers

Now, let’s take the rate of weight loss that you decided on, which was 0.6 kg per week, and calculate it into calories.

In theory, to use 1 kg of body fat as energy you must eat at a 7000 calorie deficit.

7000 x 0.6 kg = 4200

So, in order to lose 0.6 kg of fat per week, you need a weekly deficit of 4200 calories.

4200 / 7 = 600

Which equals a daily calorie deficit of 600.

Now, all what’s left is to take your daily calorie maintenance number (TDEE) and subtract it with your deficit number and you’ll have set up an optimal daily calorie deficit for fat loss.

2800 – 600 = 2200

This deficit will ensure that you lose fat quickly, but not too quickly so that it causes muscle loss and other unpleasantries.

Step 3. Slow Down Your Rate of Fat Loss as You Get Leaner

The final step is to slow down your rate of fat loss as you get leaner. This is the first part in something called diet periodization, which is an extremely powerful strategy for getting lean.

Let’s say that in this example you weigh 80 kg (175 lbs) when you start, this means that you’ll go from let’s say 18% body fat down to 15% body fat in 4 weeks by losing 0.6 kg per week.

This means that after 4 weeks you’ll be entering a new body fat % bracket, and should slow down your rate of weight loss.

Now there are many ways to reduce your caloric deficit, but I’ve found a certain method to work extremely well.

And that is by implementing refeeds!

Using refeeds to make your calorie deficit smaller as you get leaner comes with a few psychological and physiological advantages.

Why You Should Reduce Your Calorie Deficit for Fat Loss Using Refeeds

You’ve probably heard about refeed days before, right?

To refresh your mind these are days where you eat at calorie balance or slightly above in order to get a break from cutting. I recommend maintenance calories on refeed days to still keep some structure.

When it comes to refeed days, research has shown that one day at maintenance per week is not enough to provide much positive effects on a physiological level, but it has been shown to be enough time on a psychological level.

This was found when one group of researchers sent out a computer based survey to a group of subjects with the following question:

-What would you enjoy most; 7 days of straight dieting on 1500 calories per day, or 6 day on 1300 calories with 1 day at 2700 calories on the last day of the week?

These two options will result in the same weekly caloric intake by the way, which is more important than daily caloric intake, here’s a visualization of this:

Nearly all subjects choose the second option, simply because they believed 1500 and 1300 calories to be equally sucky. But that one day at maintenance, where they could indulge in more food seemed like a very enjoyable break and trade-off.

So, one refeed day per week is supported to be beneficial for mental enjoyment and better adherence to the diet.

However, one day doesn’t seem to be that beneficial when it comes to reversing negative physiological adaptations caused by a caloric deficit. Such as; metabolic slowdown, glycogen depletion and hormonal disruption etc.

What’s been shown however, is that longer refeed periods, between 2-3 consecutive days seems to be beneficial for reversing some of the physiological adaptations to the diet as well.

Where one study by Dirlewanger et al. found that 3 days of refeeding at maintenance reversed metabolic slowdown by increasing TDEE (Total Daily Energy Expenditure). This effect seemed to start already at day 2 of the 3 day refeed as well.

Also, in another study by Olson et al. They found that by having at least a 48 hour refeed in a row, they could reversed the effects of hormonal imbalances that are created during a caloric deficit. For males this is typically a lower testosterone to cortisol ratio.

And by having at least 2 consecutive refeed days per week, this ratio will be over all better throughout the cutting phase.

This will likely make you perform and feel better, while preserving more muscle mass and losing more fat.

Stacking refeeds on top of each other as you’re getting leaner overtime, seems like a great idea to effectively slow down your rate of fat loss. While doing so, you also simultaneously get some of the positive mental and physical benefits of consecutive refeeds as well.

So, how do we do this?

How to Slow Down Your Calorie Deficit Using Refeeds

Step 1 – Set up the amount of refeeds per week accordingly to your body fat percentage.

Here’s the amount of refeeds that I’ve found work best both for myself and for clients:

Body Fat % Number of Refeeds/Week 20%> 15-20% 12-15% 10-12% 8-10% <8% 0-1 1 2 3 4 5

Step 2 – Recount your calorie deficit to fit your low days and maintenance days.

Let’s continue using the same example from earlier. Where you started at 80 kg, 18 % body fat and a daily calorie intake calculated to 2200 per day, which should have you lose 0.6 kg per week.

As you can see in the list; since you’re between 15-20 % body fat, I recommend one refeed day per week.

To calculate how many calories you should eat on your 6 low days and on your 1 refeed day, you must first count your daily caloric intake into your weekly caloric intake.

2200 x 7 = 15400 calories per week.

Next would be to subtract this weekly total with 1 maintenance day (the reefed).

15400 – 2800 = 12600 calories

Finally, divide these remaining calories with the remaining 6 days:

12600 / 6 = 2100 calories

There we go, to still lose 0.6 kg per week, this time with 1 refeed day per week implemented, you should in this example eat 2100 calories on your six low days and 2800 calories on your one refeed day.

Step 3 – As you get leaner reduce your caloric deficit simply by taking one more refeed day accordingly to your “new” body fat percentage bracket.

Okay, so after 4 weeks, you reach 15 % body fat. It’s time to slow down your rate of weight loss to avoid losing muscle mass and/or experience other unpleasantries caused by losing weight to fast at a lower body fat percentage.

Now, instead of reducing your calorie deficit by eating less on all of your days, you’re smart and want the positive benefits on metabolism, glycogen replenishment and hormonal balance.

You get this by adding another refeed day at maintenance next to your already existing refeed day.

You see, by doing this you just reduced your calorie deficit and rate of weight loss, while simultaneously reversing some of the negative physiological adaptations caused by the deficit. All while you get two whole days in a row to enjoy more food.

Isn’t that awesome, right?

All you have to do now is repeat this process each time you get into a new “body fat percent bracket”.

This is the power of refeeds. In fact, I believe it to be the most powerful strategy when it comes to getting lean effectively and enjoyably.

Why?

Because by doing it, you will reduce your calorie deficit slowly over time, by taking breaks at maintenance more often, and this is definitely key for making fat loss more effortless.

What’s most powerful though, is that you’ll continue adding refeeds until you’re at a point where you’re close to maintenance calories on all your days, while also becoming leaner at the same time.

When you’re approaching the 10% body fat mark, you’re going to be at maintenance calories 3-4 days per week. The other 3-4 days in a deficit will go by so fast, and will feel very easy because you know there will be a 3-4 day break coming up very soon.

This is a form of reverse dieting and in order to get a lean and ripped beach body, I definitely think this is the best method, because it will enable you to sustain a low body fat percentage, likely year around if you so choose to.

Conclusion

So, to recap; there is an optimal caloric deficit for fat loss, which will make you lose fat quickly while also enable you to spare muscle mass and feel good in the process.

The way to set it up is accordingly to your body fat percentage.

As you get leaner you should reduce your calorie deficit. This is most effectively done by implementing consecutive refeed days at maintenance calories.

What’s Next?

Even though your calorie deficit is the most important thing to set up correctly for effective and effortless fat loss, there’s still a lot more that goes into successfully building a lean and muscular physique.

Your macronutrients (protein, carbs and fats) are very important, and so are the various dieting strategies that’ll help you stick to your calorie deficit for a prolonged period of time. Not only that, having a well set up training program is cruicial for muscle maintenance when you’re in a calorie deficit as well.

To get all of these things set up correctly I recommend that you get your hands on a high quality course. This is what I did in the beginning of my fitness journey and it’s the number one reason I was able to undergo my physique transformation sooner rather than later.

Having access to a step by step course and just following it to the T is the only real “shortcut” to building a ripped physique. You basically take what someone else learned over a time course of five to ten years and bring it down to a one, two or three year process depending on your goal and starting point.

Do yourself a favor and don’t wait ten years to build the physique of your dreams, get your hands on a guide and you’ll get there a LOT quicker. I use and recommend the Kinobody and Think Eat Lift courses, you can read more why I do so here!

I hope this article was helpful, and if you have any questions make sure to ask them in the comment section below, right now!