When most people want to get leaner, the goal is to look better naked, feel better and fit into your clothes.
Most people refer to this process as ‘losing weight’ rather than ‘losing fat’.
That might be because we don’t like to admit we are carrying excess fat and ‘weight’ is just a nicer word to use.
Some people even refer to fat as ‘weight’.
Whatever the reason, if you want to diet it’s important to respect the nuances between weight loss and fat loss, because there IS a BIG difference.
WHAT IS BODY FAT?
Fat is literally fat cells, or to give it the scientific name; adipose tissue.
We all naturally have adipose tissue on our body, but some of us carry different amounts to others.
According to the American Council for Exercise, the average body fat percentage for women is between 25-31%, and 18-24% for men.
Here are the average body fat percentages for each category of person, for both men and women;
Adipose tissue is an essential part of the body, acts as insulation, keeping us warm in cold temperatures, and provides protection for vital organs like the heart, lungs, stomach and intestines (which is why the majority of people store fat around their stomach and chest).
So, we do need some level of fat – too much however can lead to health problems like diabetes, and can increase the risk of other serious diseases.
Of course, the less fat we have on our bodies, the smaller we are and the more muscle definition we have, which is what most people strive for aesthetically.
This is why most people want to lose weight; what they’re really looking to do (even if they don’t know it) is lose fat.
WHAT’S THE DIFFERENCE BETWEEN FAT LOSS AND WEIGHT LOSS?
Fat is just fat.
Weight however is literally everything else in and on your body.
- Muscle tissue
- Food in the gut
Some of these can vary wildly, and therefore affect weight on the scale, on a day to day basis.
The three key ones that fluctuate the most however are;
- The amount of food in the gut
- The amount of water (stored in both muscle tissue and organs)
- Glycogen stores
Food in the gut will affect weight based on the actual volume (weight of food) you’ve recently eaten, and when your last bowel movement was. If you’ve eaten a large volume of food and not had a bowel movement for days – You’ll likely have upwards of a pound or two (0.5-1kg of food just sitting in your gut).
The amount of water you hold onto is affected by many things – the simplest one is obviously the amount of water you have in your gut at any given time. If you’ve drunk a lot of water and not been to the toilet then this will have an effect on your weight.
If you want to see what effect this has, weigh yourself. Then drink one litre of water, weigh yourself again. Your weight will have increased by around 2lbs (1kg).
Water is also stored in cells, organs, and muscle tissue, and the amount of stored water you have will depend on your hydration level.
Finally, muscles and the liver can store glycogen, which is stored carbohydrate. The average person can store around 600g of glycogen at any one time, meaning when your glycogen stores are topped out, you could weigh almost 1lbs (0.5kg) more than when it’s empty.
So, let’ say you weigh yourself on Monday and you’re 180lbs on the scale, if you weigh yourself on Friday, you could easily be six pounds heavier (186lbs) if you’ve eaten a lot of food, not had a bowel movement for some time, and your glycogen stores are topped up.
And that DOESN’T mean you’ve gained any fat.
This is why it’s so important to detach scale weight from the notion of losing fat.
Having said that, if you do want to lose fat, for most people (there are some exceptions), that will mean losing overall weight.
Fat does of course impact scale weight as well.
Let’s say you weigh 180lbs and have a body fat level of 25%. That’s 45lbs of fat you’re carrying.
Even if you reduced that by 9lbs, that’d make a big difference (if it was all fat loss), taking your body fat down to 20%
WHY DO THE SCALES FLUCTUATE SO MUCH WHEN LOSING WEIGHT?
These fluctuations are caused mainly by the three elements highlighted above;
- Food in the gut
- Stored water
- Stored glycogen
But what actually causes these elements to fluctuate from day to day
If your bowel movements become less regular, your weight will of course go up, then when you do eventually take a crap, there will be a big reduction. Make sure you stay regular by eating fibre and drinking water
When you eat carbs, some of them may be stored as glycogen in the muscle and liver (if your glycogen stores aren’t already topped out). This will mean your weight increases.
Additionally, for every gram of carbohydrate you eat, your body stores 3 grams of water. So, if you eat more carbs, you’ll gain more weight, but remember, THIS IS NOT FAT, so you’ve got no reason to avoid carbs, just be aware they can cause weight fluctuations
The Menstrual Cycle
For women, menstruation can lead to water retention, which in-turn influences weight, it’s good to be aware of this when it’s your time of the month
Stress, caused by lack of sleep or heavy workloads can cause a spike in a hormone called cortisol, which can lead to water retention.
The key thing to remember is that ALL of these things will cause some day-to-day fluctuations and it’s partly outside of your control.
This is why, when losing fat, it’s much more important to look at week-to-week progress rather than day-to-day, because a lot of the noise gets eliminated.
HOW TO LOSE FAT, RATHER THAN WEIGHT
So, fat loss, rather than weight loss per se should be the goal.
But how do you lose fat?
Well, you need to make sure you’re in a calorie deficit. This means consuming fewer calories than you use on a daily basis over a long period of time.
Being in this state means you’re providing the body with a little less energy than it needs to survive, so to make up the deficit, it’ll start burning through some stored body fat to provide energy.
This is a slow process but it’s the ONLY way to lose fat.
Now, of course, losing fat does mean losing weight, so you’ll need to use the scales to track your progress over time.
But scales aren’t the only way to measure your fat loss.
HOW TO MEASURE FAT LOSS
The most accurate and reliable way to measure fat loss is with a DEXA scan.
You’ll have to go to a hospital or specific lab that offers this service – and they;re not cheap – most DEXA scans cost around £150 per session.
But they will tell you with a high degree of accuracy your muscle to fat ratio.
Would I recommend getting one?
They’re expensive and kind of pointless, because let’s be honest, no one really cares about your body fat percentage, all you really care about is how you look, feel and fit into your clothes, so, I personally these methods are much better forms of tracking fat loss progress;
Body-Part Circumference Measurements
Measurements will tell you whether or not you’re losing fat in the places you really care about.
For most men, this will be the waist and chest, and for most women, the waist and hips.
Here are instructions for taking these measurements;
Chest: Measure around the nipples
Waist: Measure around the belly button
Hips: Measure around the highest point on the hips
The tape measure doesn’t lie!
Remember, when it comes down to it, numbers on the scale and on the tape measure don’t really matter, what most of us really want is to look better.
So, progress photos are a great way to judge (subjectively at least) how we look.
You might think looking in the mirror is enough, but because you see yourself everyday, you won’t notice the change over time.
If you take photos at regular intervals however, you’ll see the visual differences.
If you’re going to take progress photos, remember to take the photos in the same room, from the same angle, at the same time of day, and with the same lighting!
Now, there are also some common measurement methods I would avoid, these are;
Calipers are vice-like devices that are designed for ‘pinching’ the skin in predetermined points on the body. The size of the skinfold that can be pinched gives an estimation of your body fat percentage.
The problem with these however is that they present WAY too much margin for error.
For example, different sets are configured in different ways.
Even if you use the same set, the person using it will have a big influence on exactly where the skin is pinched and how hard it’s pinched, meaning there’s the potential for wildly inconsistent readings.
Bioelectrical Impedance Scales
These are commercially available scales that claim to be able to measure body fat.
They work by sending a small electrical current through the body and back into the scales.
The better the body conducts electricity, the less body fat you have (in theory) since body fat doesn’t contain water (and therefore doesn’t conduct electricity).
The obvious issue with these is that your current hydration level will have a huge impact on the reading.
So scale weight, plus measurements, plus progress photos combined are a great way to keep tabs on whether or not you’re actually losing fat.
Disregard anything that claims to give an accurate body fat percentage reading, because ultimately nothing really can (aside from a DEXA scan), and even if they could, body fat % doesn’t really matter anyway.
WHEN MIGHT YOU LOSE MUSCLE?
Something a lot of people worry about when losing weight is losing muscle.
And this is a legitimate concern.
If you lose equal amounts of muscle and fat, you can end up being ‘skinny fat;’, i.e. just a smaller version of yourself.
If you just lose fat, you’re going to end up looking a lot better as you’ll keep your muscle, which gives you shape in the areas where you do want it (generally shoulders, chest and arms for men, and glutes and quads for women), but lose inches and centimetres off of areas where you don’t want it, i.e. your stomach and hips.
So, you want to lose as much fat and as little muscle as possible.
How do you do that?
- Lose fat slowly
In a calorie deficit, the body will burn fat primarily for energy, but if the deficit is too big, it will also start cannibalizing muscle tissue for energy.
The bigger your calorie deficit, the more of what you lose will be muscle. If you lose weight in a conservative fashion, you’ll minimise the risk of muscle loss.
For most people, I suggest a 0.5-1% drop per week of your total body weight.
So if you weigh 180lbs that means aiming to lose 0.9-1.8lbs per week
If you weight 80kg, that means aiming to lose 0.4-0.8kg per week
- Keep Protein Intake High
Protein helps to build and maintain muscle.
Eating a decent amount of protein is even more important when dieting.
Aim to eat around 0.8g of protein per lb of body weight.
This means that if you weigh 180lbs, you should eat 144g of protein per day
- Continue to Resistance Train
If you currently train with weights, carry on.
If you don’t, consider starting.
Using your muscles will tell your body that you need to keep them.
This meta analysis found that;
“a progressive resistance exercise training program in conjunction with a hypocaloric diet attenuated the weight-loss–associated loss of muscle mass in middle-aged and older men and women”
2017, Cava et al
CAN YOU DROP BODY FAT WITHOUT LOSING WEIGHT?
This is a controversial one.
The answer is technically, yes. But it’s quite tricky, and quite a rare thing to happen.
In order to lose fat but not lose any weight, you’d need to be losing fat AND gaining muscle simultaneously.
This process is called recomposition.
While recomposition sounds like the dream scenario, the truth is that for most people, focusing on either losing fat OR gaining muscle is a better option.
This is because, with recomposition, the rate of both muscle gain and fat loss is VERY slow. For this reason, the best candidates to adopt this approach are those that have been training for a long time and are very close to their ideal physique and are at the point where they need some fine-tuning.
In order to recompose, you need to eat around maintenance calories and resistance training using progressive overload.
DOES DIETING MAKE YOU LOSE MUSCLE?
If you diet too quickly, you can lose muscle.
In reality, anyone that diets will lose a small amount of muscle, so when you diet you should be thinking about mitigating muscle loss as much as you can.
But how can you tell that you’re losing muscle?
You’re Getting Weaker in The Gym
If your major lifts are going down, ie. you’re doing less reps, or able to lift less weight (or both) that’s a sign you’re getting weaker, which could be an indicator of muscle loss.
If you’re losing a lot of weight, this will be inevitable at some point, but certainly not early on in a diet.
Make sure you’re using an app like Rep Count to keep a close eye on your progress.
As well as being able to spot changes in body fat in your photos, you should also be able to spot a reduction in muscle tissue.
Are your shoulders and chest getting narrower? If so, You could be losing muscle
Again, you can use the same process as the one you use for measuring your chest, waist and hips, but this time measure the circumference of your shoulders and upper arm. If these measurements are dropping rapidly, you’re likely losing muscle.
When dieting, it’s important to be aware that fat loss is the target, not overall weight loss. This is why it is as important to look at progress photos and body-part circumference measurements AS WELL as the number on the scale.
Don’t worry about your weight on a day-to-day basis, it WILL go up and down regardless of what you do.
The key thing to pay attention to is your weight over the long term, i.e. months.
Finally, if you want to lose fat, you HAVE to be in a calorie deficit, there’s no around that. If you need help with your diet, get in touch with me.
What are the guidelines for percentage of body fat loss?: https://www.acefitness.org/education-and-resources/lifestyle/blog/112/what-are-the-guidelines-for-percentage-of-body-fat-loss/
Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans:https://pubmed.ncbi.nlm.nih.gov/25911631/
Effects of psychological stress on plasma interleukins-1 beta and 6, C-reactive protein tumour necrosis factor alpha, anti-diuretic hormone and serum cortisol:https://pubmed.ncbi.nlm.nih.gov/8266000/
Preserving Healthy Muscle during Weight Loss:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5421125/
Fundamentals of glycogen metabolism for coaches and athletes:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019055/
Joe is an online weight loss coach and qualified personal trainer of 15 years who helps busy, professional men and women lose fat and build muscle.
Having a 9-5 desk-job, Joe understands the struggles of juggling a hectic life with trying to maintain a good physique.