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Weight loss vs Fat loss: What's the difference?

Chances are, you’ve probably tried to lose weight at some point in your life. That ‘New Year, New Me’ diet after binging on all those Christmas carbs, that bid to eat healthier and workout more when you discover that “omg, it’s only 6 weeks until my summer holiday!” But, what’s the difference between losing weight and losing fat? Believe it or not, it’s definitely not the same thing. We’ve dug a little deeper to explain the difference between the two!

What is weight loss?

So, put simply, your body weight can be divided into two main categories: fat mass and lean mass. Fat mass is exactly what is sounds like – your total amount of body fat. Lean mass is anything that’s not fat mass, for example, bone mass, organ mass, muscle mass and the water within your body.

When losing weight, we unfortunately can’t decide which part of our body weight we shed. Weight loss is simply a numerical measure and doesn’t consider the quality of what’s lost or gained. For example, cardio bunnies who take on a new weight-lifting regime are likely to put on weight, despite working out harder than before. This shouldn’t be perceived as negative, as muscle mass weighs more than fat. Another example is those who switch from a high carb diet to a low carb diet – they’re likely to lose significant amounts of weight because 1g of stored carbs holds around 3g of water in the body, meaning you may weigh more despite not eating any more calories.

It’s important to remember that a number of factors can cause weight fluctuations. From sodium intake to food sitting in the gastrointestinal tract, there are a number of reasons why you may hold more weight or find it harder to drop the pounds.

So, what is fat loss?

If you’ve been searching for ways to drop fat, you’ll have probably stumbled across the two most common types of body fat: subcutaneous fat (this is the fat between the skin and the muscle) and visceral fat (this appears around your organs). These two fat types are responsible for your body’s health and appearance. When you lose fat, it’ll be one of these two types of fat you’re shedding.

As with body weight in general, we can’t choose where we lose fat from. So, smashing out those crunches won’t automatically give you a super toned, fat-free stomach. Experts advise that you must be in a slight calorie deficit in order to see any fat loss but always ensure you are eating the right amount of calories and getting the correct macronutrient balance to support your lifestyle.

Remember, everyone has body fat – it’s essential and nothing to be scared of! Our body fat is expressed as a percentage of our total body composition. For example, 20% body fat. Women tend to have more body fat than men, as they need higher levels of fat to maintain their reproductive system. An average healthy man can have up to 24% body fat, while an average healthy woman’s body fat percentage could be up to 30%.


Should I track weight loss or fat loss?

There are a number of reasons why tracking weight loss and weighing yourself aren't always the best way to track your progress. Many factors can make simply weighing yourself on the scales an unreliable representation of your progress.

Water retention

Yep, how much water you drink and how much sweat you expend will dictate how much you weigh! Sounds crazy but, think about it: water weighs a lot. 1L of water weighs 1KG, so if you’re weighing yourself before you’ve been to the toilet, you’re likely to be heavier. This works the same way for water expenditure. When you sweat, your body loses water so you’re likely to be lighter due to being dehydrated.

Muscle loss

Stopped hitting the dumbbells due to injury? Or maybe you’ve worked more cardio into your regime and cut back on the curls. Whatever the reason, muscle loss may cause your weight to dip on the scales. Muscle loss can also be caused by being in a greater calorie deficit for your body. The body isn’t able to lose kilograms of fat per week so, instead, muscle will be metabolised if your calorie deficit is too high. If you’re dieting, it’s essential that you consume enough protein as part of your new diet to ensure that you maintain your body’s muscle mass.

Drastic calorie deficit

Of course, in order to lose weight, you need to be in a slight calorie deficit. However, drastically cutting back on the calories can be dangerous and is simply unsustainable. Restrictive dieting can cause binging and those who cut their diet right back are more likely to put the weight back on. Studies suggest that calorie deprivation can lead to changes in a variety of cognitive and attentional functions*, with dieters focusing a lot of their thoughts on food. This could cause unhealthy relationships with food, making the dieter more likely to restrict then binge and, in turn, put on weight they’d lost back on.

How can I measure my body fat percentage?

The easiest way to measure your body fat percentage is by using a calliper. Using at least 3 areas on the body (abs, thighs and chest are good areas to use) pinch the skin, pulling the muscle away from the fat, and measure the fold with the callipers. It is recommended to test on the same side of the body and take the average of two measurements at each area. Then, pop these measurements into an online body fat calculator and this will give you your body fat percentage.

If you prefer, you can ask your doctor to check your body fat percentage, especially if you have any concerns. Pharmacies, leisure centres and gyms also often have machines you can use for a small charge that will measure your body fat percentage.



Struggling to shed that dreaded COVID-15 weight you’ve gained during lockdown? These 7 weight-loss myths may explain where you’re going wrong. Want to keep on track of your diet? Why not read our guide to tracking macros. Plus, there’s also a whole host of home-workout inspo over on our blog if you need a push to get active!