Fast or slow fat loss?

fast or slow fat loss edinburgh pt

It’s not unusual for someone to come to me and say something along the lines of, “I’m going on holiday in 3 weeks, what can I do for fat loss/ how do I lose these (pointing at the fat on their underarms)/ get a 6 pack?” And the answer is always the same – start 6 months ago…

The truth is, that there’s not much you can do to make as much progress as these folks want in such a short time. I mean, sure, you could crash diet, drop a few kgs of mostly glycogen, water weight and lean mass. Then feel so bad that an airport binge is all but inevitable and the weight goes back on by the time they’ve landed in the sun.

That said, there can be a good case made for fast(er) fat loss, as can be made for slower, more gradual fat loss. So in this post I’m going to take you through the pros and cons of each approach and hopefully help you decide which approach is right for you.

How fast is fast?

So before we can look at the pros and cons of fast and slow rates of fat loss, just how fast is fast? Or slow?

For most studies, fast fat loss is at a rate of about 1-1.5% of bodyweight lost per week. So if you are 80kg, you would be aiming for a loss of 0.8-1.2kg in week 1, 0.75 to 1.1kg in week 2 etc. That’s about 1.5-2lbs per week in backward parts of the World where they don’t use metric measures.

Slow weight loss is measured at less than or equal to 0.5% of bodyweight lost per week. So our same 80kg starting weight would drop by 0.4kg (0.9lbs) per week.

For most people, going over 2% loss per week is unadvisable due to the large calorie deficit required. This may change, however, if you have a significant amount of weight to lose and the deficit to do so isn’t as large relatively speaking.

The pros of going fast!

You’ll get there faster for a start. Faster fat loss, with a more aggressive calorie cut, shortens the length of time you are going to be in a fat loss phase. This can make the process easier mentally, since you know that it’ll only last a few weeks rather than a few months.

And seeing the results come in faster, can be a massive boost in motivation, helping you keep going when it inevitably gets a little tougher.

Not so fast…

It would seem on the surface that faster fat loss has a lot going for it, you get quicker feedback that you are doing the right thing and you get to your target more quickly. But, as with all things, there are downsides to consider.

Bigger calorie drops will obviously result in less energy to work with, possibly leaving you feeling lethargic. Also meaning you’ll struggle to fuel your training sessions adequately resulting in a drop in performance and recovery.

You will likely lose more lean mass and correspondingly less fat mass in your overall weight loss. And since the goal is to lose fat, you’re limiting your potential progress.

Bigger calorie deficits also make transitioning back to a new maintenance calorie intake a little harder to do without adding back a lot of your lost fat. This is partly due to a slightly higher adaptive drop in metabolic rate and loss of lean mass caused by the bigger deficit. While these tend not to be huge in their effect, they will have an effect on your new maintenance calorie intakes in the short term.

Plus, you’ll be hungry a lot of the time…

The case for slow

If we look at a slower approach to fat loss, most of the cons of a faster approach are negated:

You get more energy to play with each day, meaning a minimal drop in performance and more energy generally.

You will maintain more of your lean mass, thereby maximising your fat loss, and having more of a toned shape (a term I hate, but anywho…) to show at the end of your fat loss process.

You’ll also find it easier to transition to maintenance once you’ve achieved your goal since the difference between the deficit and maintenance numbers will be smaller at the time you hit your target.

And finally, you’ll be less damned hungry all the time. And that is a big plus in my book.


I did say that there were cons to both fast and slow approaches, so let’s look at the negatives of a slower approach.

The most obvious downside is that it’ll take you longer to get there. A smaller calorie deficit, while more manageable for most people, means that progress is slow. Week on week you’ll see less of a change in both scale weight and body measurements, and this can negatively affect motivation and make it harder for some to keep going.

So what should you do??

The approach you should take depends on a lot of things, you’re preference over a long, sustainable option, or a faster, get it over with quickly one. Do you handle hunger well? Or do you get hangry pretty easily? How much fat do you want to lose? Do you like to eat out more often? What is your training approach like? Etc etc etc.

What do you notice about all of these questions?

That’s right, they all ask what you prefer. Because ultimately that’s what this is about, finding out about your needs and preferences and finding the approach that is right based on those factors.

So consider your needs, and your preferences and that will help you zero in on the right approach for you. There’s is no right or wrong here, but you need to decide what is best. And that might include a start fast, transition to slow approach which would get you off to a fast start, gaining momentum and motivation, then transitioning to a slower more sustainable approach to take you the rest of the way.

Whichever option you choose, be consistent and you’ll get the result you want.

Stay healthy,


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