I am sorry ladies and gentlemen, but some of you are not going to enjoy reading this because it is going to ruin one of those little white lies we tell ourselves. But trust me, it is in your best interest long term that you know the truth. So, have you ever got on the scales to see it go up, and you say: it’s OK because I have been going to the gym loads, and muscle weighs more than fat. Wrong! Letting yourself believe this age old myth could be sabotaging your weight loss. So what is really happening? How does exercise really effect weight loss?

 Muscle DOES NOT weigh more than fat.

I know what you are possibly thinking, but Jennie, you hear it all the time: muscle weighs more than fat. So let’s get that age old myth out the way first. A tonne of bricks and a tonne of feathers both weigh a tonne, and pound of fat and a pound of muscle both weigh a pound. So where has this strange muscle weighs more than fat myth come from? Well the difference is not the weight but the composition of muscle and fat. Think of that tonne of feathers: it takes up a lot more space than a tonne of dense heavy bricks. The same is true of muscle and fat. Muscle is much more dense than fat, so 1lb pound of muscle takes up less space than 1lb of fat. This can be hard to understand as we have probably never seen a tonne of feathers or 1lb of muscle. One of the best analogies I heard of this was to think about potatoes. Take two 300g potatoes, they are firm and solid as they have a dense texture, this is like muscle. Now take those two 300g potatoes, boil them and mash them up. The same amount of potato now looks all lumpy and bumpy, much more similar to the density and composition of body fat. So yes, two people who are the same height and weight can look very different depending on how much of that overall weight (mass) is fat, and how much is lean muscle.


A tonne of feathers and a tonne of bricks are the same weight but different density and volume.


What happens to our body when we exercise?

Exercise can do lots of things to our body. Obviously we get hot and sweaty and ache, but I mean long term, what happens to our body composition when we get more active. Well exercise does one of two things for our body: it helps to burn fat, or it can help to gain muscle. Which of these happens depends on the type of exercise we do.There are two primary types of exercise: cardio exercise and resistance training. Cardio exercise is things like: walking, running, swimming, aerobics, Zumba, dancing, cycling, using the cross trainer or the treadmill- basically anything that gets us moving about and increases the heart rate. Resistance training means using added resistance, usually weights, that can include anything from the weight machines, free weights like dumb-bells, kettle bells, resistance bands even your own body weight in things like push ups and pull ups. So how do they differ on the body?

Well very simply put, cardio based exercise predominantly burns fat, resistance based exercise are effective at building muscle. So if you are doing mostly cardio based exercise then you are mostly just burning fat, and not building much lean muscle. Cardio exercise is a great calorie burner so you’re clever body will be burn up some of its excess body fat. Without added resistance, there will be no muscle gained. There may be some slight improvement in muscle tone as you strip away fat, but you are not going to be building any muscle, therefore your overall weight should continue to go down. Less body fat and no increase in muscle mass= overall weight loss. So if you are mostly just doing cardio based exercise like running, swimming, cycling, or Zumba, then your weight loss should continue to go steadily down.


5lbs of body fat compared to 5lbs of lean muscle

If you are doing resistance training, then it is more likely you will be building some muscle, therefore you may see your weight loss slow down, or even a slight increase at the scales. BUT DO NOT PANIC. For most people who are only lifting moderate weights just a few sessions a week, then the amount of muscle gained will not be huge. Plus, most people trying to lose weight are also eating better and probably doing some form of cardio based exercise, and are therefore you will be losing fat whilst building lean muscle. Therefore, we should again see an overall loss in weight overtime. For example; for every 1lb of lean muscle gained you will probably lose 2-3lbs of body fat, so your weight will continue to go down, though it may be slower than if doing just cardio based exercise, and may even seem slower than if we doing no exercise at all!

Does this mean I shouldn’t do resistance based exercise?

Hell no! There are lots of reasons why you should do resistance training, not least to improve strength and power, improve bone density, decrease risk of injury as you age, but most importantly to look awesome. Think about those potatoes. Do you want a bottom that looks all squishy like mash, or do you want a nice toned bottom like a couple of firm potatoes in a hanky. Plus, did you know that muscle burns more calories than fat when you are at rest. Yes it is true fact- if you have more muscle on your body you will burn more calories at rest. Amazing right! That has to be worth a slower rate of weight loss!  The NHS website is a great source of information on the health benefits of exercise.

The exceptions

I know already some of you are now screaming at the screen thinking, nooooo! I have experienced this; I started exercising and my weight loss slowed right down, or worse went up. I will explain a few reasons why this may be in a moment. But first we must say that there is of course always exceptions to the rules. And anyone who reads this blog each week will know I have spent the last nine weeks taking part in my own healthy bikini body challenge, and in that time I have seen a huge difference in my body, but very little difference in my weight. And last week I said that this was due to a notable loss in body fat and a significant increase in muscle. So yes this might now sounds like I am completely contradicting myself, but there’s a few things you need to consider that make my situation an exception not the norm. Firstly, I am a qualified personal trainer and I have been doing heavy and advanced weights training for about 5 years now, I wasn’t starting from scratch.

The level of muscle gain I have seen over the last 9 weeks is not typical of people just starting to exercise.  So please do not panic that starting a weights based training programme will see you rapidly gain muscle and consequently weight. Prior to starting my bikini bod challenge I had taken about 2 months off my usual training regime due to surgery. Once I started my challenge and got back to my weight training I was able to rapidly increase the amount of weight I have been lifting. It is not advised that you quickly increase the amount of weight you are using if you are not either a; qualified fitness professional, or b; under the very close supervision of a professional trainer. It is of course not impossible, it does happen. If you have started using, or increased your weights training (in amount or intensity) then there may be some muscle gain, and a consequential increase in weight, or slower pace of weight loss.


Many people massively overcompensate in treats after exercise

There a few more common reasons why we see an increase at the scales when we start exercising that have nothing to do with muscle gain, and this is what you might not want to read, but I promise it will be good for you in the long run! Now you know the truth you can stop using that old excuse and boost your weight loss. There are many reasons why we can see either a drastic slowing down, or worse an increase in weight when we start exercising.

Inflammation: if you go from no exercise to quite an intense pace of exercise very quickly then you may experience see some inflammation. Just like if you sprained your ankle- fluid rushes to the area and it swells. If you have been aching after an exercise session, then there may be some inflammation in the recovery process. This however should only be very temporary. Your body will quickly adapt to the new level of activity, then your weight loss will continue.

Increased appetite: this is the most common. When we start exercising, or increase levels of activity we will mostly likely have an increased appetite as our body burns up more energy. We may not even notice how much portion sizes have crept up, and simply put- what you put in your mouth will have the biggest impact on weight loss. Which leads to the next reason we can see some weight gain when we increase activity:

Thinking we can out-train a bad diet: Most people massively overestimate the level of activity done or the amount of calories burned. Thinking: oh, I did that spin class, so I can have a takeaway, or a dessert. Or thinking a jog on Monday morning will undo the damage of a heavy Saturday night on the vino. This can be very damaging to your weight loss and healthy lifestyle.

The disappointing fact is that an average 40 year old women, weighing 11stone would need to jog continuously for about 86 minutes to burn the equivalent calories to a Harvester Rocky Horror Sundae. That is roughly equivalent to running a 10km race, for one ice-cream!

You may be readying this now and wondering: why bother? Sounds like exercise is just going to make my weight loss journey much tougher, but you couldn’t be more wrong. The benefits of being more active extend way beyond weight loss. As I have said so many times in past blog posts; it’s not always about the scales, the non-scale victories are so much more important. If you feel you are seeing a slowing down of your weight loss, or an increase in your weight, and you are unsure if it is muscle gain or one of these reasons above, then look off the scales. Take your measurements, take some progress photos, look how your clothes fit. If you bottom is looking a little more raw potato and a bit less mash, then who cares what the scales say!

Bikini body challenge update

I forgot to take my pics on Sunday night! I had such a busy weekend of celebrations that it didnt even enter my mind! Then I have been home alone, so nobody to take them! Plus the whole challange has become less of a challenge now. I think it has finally become routine. There is however just 3 weeks left, so I may step up the pace a little :) But, I am feeling a lot better and have noticed lots of non-scale victories. Getting dressed up my sisters 50s themed party this week helped me recognise some of my recent success. The shorts I am wearing here didnt fit 9 weeks ago, and not only did they fit but I felt good!


Feeling good in short that didnt fit 9 weeks ago is much greater feeling that any change in numbers


Not being conscious at my sister party this week was a great feeling. It felt nice to be confident in my 50s themed pin up outfit and not worrying about having my photo taken in goofy pictures. No scale will ever show you that feeling












I am Jennie, founder of set U free fitness, and Weight Watchers leader in Leeds. I lost 7 stone with Weight Watchers and transformed by body through exercise. I always dreamt that life after goal would be easier, but the reality is- it’s not. This personal blog is my ongoing journey to stay healthy and happy. It is a collection of my thoughts, tips, lessons learnt and mistakes made in trying to create a balanced healthy lifestyle that I can follow for life. I always love to hear your thoughts, and hear from people undergoing similar journeys, so please comment or get in touch