please please please stop crash dieting

How much weight can I lose in a month?
Grow Like Oak
how much weight loss one m

How much weight can I lose in a month?

When I get asked this question it gives me a good sense of the motivations of the person. If you’re asking this question, it’s likely you’re getting in shape for “a season” not  for “a reason”.  Meaning – you’ve got a wedding coming up, summer is just around the corner, or maybe you’re an athlete making a weight class. Either way it’s more of a short term goal than a long term one.

Truth is, there’s no real answer to this question.  We know that to lose weight, the answer is in calorie deficit.  Short term weight loss can be achieved by moving more, and eating less. The classic 500 calorie per day deficit (3500 cal per week) results in roughly a 1/2 kilo loss per week. 2kg per month.  Theoretically, if you’re willing to cut calories by 1000 or 1500, you could essentially loose double or triple that amount.  It’s not unheard of that people have lost up to 20kg in a month.


But not so fast friends

I’m going to go on record here – Such an aggressive weight loss is something I strongly discourage people to pursue.  The faster you lose weight, the more likely you are to gain it back, AND the faster it’ll happen too.  If that wasn’t scary enough – the harder it’ll be to lose again in the future.  Now this might seem like just scare tactics, but what I’m saying could not be more true.

If you do not NEED to lose weight so quickly, i’d strongly suggest against it – and I’m going to explain why in a moment.  However, if for any reason you REALLY do need to, or you’re just not willing to accept the “sustainable” approach as an option, I can’t fight that.  So i’ll explain how you can do it without as much of a backlash.


Your body just isn’t into weight loss

When we lose weight quickly, it signals our inner weight loss defence system. Our body’s are designed to resist rapid weight loss as much as possible.  It may seem counterintuitive considering how much we know about the heath effects of overweight. None the less, and no matter how overweight someone is, the weight loss defence system is activated.  Our bodies just aren’t into weight loss.

It’s is a natural survival mechanism that evolved in us so not to starve to death. During hunter gatherer times, when famine struck, our physiology adapted to help us get through without dying. Adaptations were also made to make sure we’re ready for the next famine too.  Metabolic rates would drop to conserve energy. Muscle would be easily broken down for energy rather than fat. Fat is the best form of energy storage & the body wants to hold on to it as much as possible.  Hunger signals are increased significantly to encourage urgency for the hunt, and as soon as food was available, storage of these calories to fat is ramped right up. The body knows that it needs to capture every bit of this energy so that it’s ready for the inevitable famine to come.

We haven’t changed a bit.  Even though we drive fancy cars and order food from our iPhones, we’re still genetically the same human being as our hunter gatherer ancestors.  So by going on a 1000 or 1500 calorie deficit for the next month, we’re telling our body and brain that there’s a famine out there.  The greater the calorie deficit, and the longer it goes on, the greater this metabolic adaptation will be.


What does this mean for the crash dieter?

So let’s say you currently maintain your body weight at 2500 calories (maintenance calories) .  If your goal is to lose 6kg of weight in a month, you’ll likely drop your calories by about 1500.  You’re now consuming 1000 calories per day.  It’s hard work, but it’s only a month, and it’s worth it, right?


Over the course of the month your maintenance calories are slowly dropping. It could be as low as 1200 by the end of the month.  You go to the wedding, the beach party or compete in your sporting weight class. Once the big event is over, what do you do on day 31? Day 32? At the very best you go back to eating your normal 2500 calorie diet.  We won’t go into the worst case scenario.

Now if your new maintenance calories are 1200, and you’re consuming the 2500 you used to enjoy, you’re now consuming 1300 calories too many.  These calories are going to get stored – and because we now know the defence system well – it’s getting stored FAST. Your body has actually been preparing for the very moment excess energy becomes available. It’s fat storing efficiency is at it’s peak.

Although this is a bit of a deviation from the original question – if you can get away with the conservative approach of no more that 1/2kg (1lb) per week, you’ll be sure to lose the weight AND keep it off.  This is a sure thing.  I even suggest having periods of eating at maintenance calories to prevent any metabolism drop.

Keeping the metabolism high is the key to losing weight forever, feeling great, and having freedom to eat (almost) anything you want.


What if you just HAVE to lose the weight fast?

If you have to restrict calories so aggressively, it’s important that you’re already thinking of the diet after the diet. This is where almost all dieters go wrong.  As mentioned, if you restrict so heavily for a month and then just go back to normal life, it’s gonna slingshot you right back to where you came from.

To reduce the after affect, you’ll need to reverse diet.  Reverse dieting means continuing to monitor your calorie intake beyond the initial month of dieting, and gradually increasing your intake over a course of weeks or months.  There’s no knowing how much of an impact the aggressive restriction will have on your metabolism, so it’ll mean starting conservatively and adjust along the way.

Before we get into the details, let’s discuss what to do while on the diet.  Over the month that you’re restricting calories, ensure that you’re eating sufficient amounts of protein to maintain maximal muscle tissue.  This should be around 2.0-2.4g per kg of lean body weight. If you have quite a high body fat percentage, go by your goal weight and multiply that by the grams of protein.  Perform some full body strength training 2-3 times per week and focus on heavy sets of 6-10 repetitions. With good form of course.  Stay away from cardio because this will only promote metabolic adaptation and muscle wasting.  You want to do all you can to maintain muscle mass and prevent the body from thinking it’s gonna die.  Drink plenty of water, get plenty of sleep and keep other stressors in you life to a minimum.  A topic for another day – but just know that overall daily stress impacts the rate of metabolic adaptation too.


The reverse diet

Reversing out of a diet needs to be done with careful attention to calories and macros. Continue to track your intake and add 5-10% more calories per day for the first week. Track your weight at the same time. If your weight stayed stable or increased only a couple of grams, increase calorie intake to 10-15%.  Where should these calories come from. Once again, protein is the key macro in this situation, for the same reasons as above, and because your body will be excited to store fat or carbs as body fat as soon as it sees enough of it. This doesn’t mean eliminate all carbs or fats, it just means focus on increasing calories through protein.

It’s important to know that with even small increments you may see an increase in weight again. Your body is fighting to bring you back to set point. By panicking and dropping calories again, you will only reinforce the problem. If weight jumps too much with an increase of calories, maintain that calorie intake for a week or two and see what happens. If it stabilises, continue with the gradual increase. If it drops, this is a possible sign that your metabolism is increasing and you may want to increase calories a bit more.

While reverse dieting it will be best to still stay clear from cardio or high intensity workouts. You don’t want the hard core calorie burn. You want to maintain or build muscle. Ladies, this doesn’t mean you’ll bulk up. You can slowly introduce small amounts of cardio when your metabolic rate is consistently on the way back up. This is when calorie intake is coming up without gaining weight.


So how much weight can you lose in a month?

Potentially as much as 20kg. Some magic potion salesman may tell you even more.  But will you keep it off?  No.  This is what has gotten so many people onto the yoyo dieting rollercoaster. Tying to lose weight for a season or event.  Either that or going hard in the beginning, hoping that it’ll stick this time round. Unfortunately there hasn’t been enough talk about the weight loss defence system.  Now that you’re aware of why aggressive dieting almost always fails, decide whether you really need to lose a lot of weight fast, or if it’s just impatience.  Knowing that the slower the better, now you just have to decide how patient you’re willing to be.

If you want to read more about the Weight Loss Defence System check out this post – Please stop crash dieting
And share this article with friends who’ve gotten stuck in the yoyo dieting loop too.



This is a boxed content block. Click the edit button to edit this text.

Don't want to miss future content?

Join the GLO mailing list

Recent from the blog

We are Animals

I’m sitting on the train and I see a girl opening a Kinder Surprise chocolate bar.  You know they come…

5 reasons you’re struggling with weight loss

This blog post is a bit of a summary from my ebook “Your Brain Makes You Fat”.  I’ve pulled out…

Health Success Through Consciousness

Health Success Through Consciousness If you want to improve your situation, namely lose weight and get healthier, it’s necessary to…


Leave a reply

Your email address will not be published. Required fields are marked *


Want to know more?

Get in touch