Fat loss vs. weight loss

Written by Trey Reck

Medically reviewed by Josie Porter, RD

Published on January 12, 2023 | Updated on March 28, 2024

Fat loss vs. weight loss: They’re not the same thing. 

Although the terms are often used interchangeably, they mean something quite different, and it’s more than just a linguistic distinction. 

Weight loss is what you see on the scale. It’s the sum total of all the stuff in your body … and when you weigh less, you have less of all that stuff.

Fat loss means having less body fat — the squishy stuff on your body. When you lose fat, you might get smaller or leaner … but you may not weigh less necessarily.

Whether you lose weight and/or fat matters for your goals. 

For instance, a lighter weight doesn’t necessarily lead to a leaner body. You can become toned, ripped, or muscular without losing as much weight as you think (or potentially any weight at all).

For improving your health, fat loss is key. When your body fat is right for your body (you can have too much or too little), your risk of health conditions like heart disease, stroke, and diabetes etc., drops. 

Weight loss, on the other hand, may or may not be. You can weigh less yet still carry more visceral fat — the kind that sits around your heart and other internal organs — than is healthy, for example.[1] 

So when you think about your goals:

Is the transformation you want to see in your body achievable through weight loss? Is fat loss what you’re really after? (Or both?)

No doubt your goals are complex and unique, just as you are. So, we’re going to unpack both weight loss AND fat loss:

• what they are
• how you achieve them
• what they mean for your body  

Let’s get into it. 

Key takeaways

• Weight loss and fat loss are two different things.
• You can lose weight through losing water, glycogen, muscle, bone, or fat.
• Losing fat can improve your metabolic health and lower your risk of medical conditions. 
• Focusing on fat loss can give you the best of both worlds.
• Defining what success means to you is crucial.

What is weight loss?

Weight loss simply means your body weighs less. But less of what, exactly? Remember, our bodies have lots of stuff in them.

When you lose weight, you might lose fat. Or, you might lose water, muscle, glycogen, or bone. 

Each of these losses will have a different impact.

• Losing fat generally means you will look more toned, because your muscles will be more visible. Your clothes will likely fit better. Your metabolic health will increase. 
• Losing muscle will decrease your metabolic health. It’ll be harder to maintain your weight, you’ll be weaker, and your risk of injury will increase.  
• Losing water and/or glycogen is temporary. In fact, your water weight changes throughout the day, every day, as your body seeks to maintain its equilibrium. Choices you make — like eating a salty meal or cutting carbs — can have a very quick impact. If you have a menstrual cycle, hormones can also affect fluid levels over the course of the month.

After starting a diet, those quick, initial drops in weight you see are water and glycogen. Glycogen is a form of fuel that your body stores in your liver and muscles. Not only does it store energy, it also stores water. When you cut calories, your body uses your glycogen stores for energy and releases the accompanying water (three grams of water for every gram of glycogen).[2] But once your glycogen stores are replenished, any related weight loss vanishes. 

• Losing bone density increases your risk of osteoporosis, which puts you at greater risk of getting injured in later life. 

(By the way, another less-glamorous type of weight loss is a bowel movement, though of course this is temporary. Many fad diets and “cleanses” help you lose weight by pooping … but that doesn’t last.)

We’ll guess you’re looking for a sustainable, measurable, noticeable change in your body. Right?

For that, fat loss is key.  

What is fat loss?

Fat loss is when your body sheds fat. You can lose:

• subcutaneous fat, the kind that lives under your skin
• visceral fat , the kind that lives in your abdomen and around your vital organs
• intramuscular fat, which is marbled into your muscles (just like the steak you see in the grocery store)

Fat loss may — or may not — result in weight loss, depending on what else is happening in your body. 

For instance, if you’re adding muscle through strength training as you are losing body fat, your weight may stay the same or even go up (if you, say, lose 1 lb of fat but add 2 lbs of muscle). 

As we’ve seen, the scale doesn’t give details. So how do you know if you’re losing fat weight vs. losing muscle weight or water weight? 

You might be able to access DEXA scans, hydrostatic weighing, or full body BIA through your doctor or a private health clinic. These are the most accurate options for measuring body fat, but they can be expensive and hard to get hold of. 

At SIMPLE, we recommend the following two options:

• Body measurements using a tape measure. You could stick to waist circumference, which can give you a good indication of your visceral fat level, but measuring multiple sites, like hips, leg, arm, chest, and shoulders too, will give you a fuller picture. You can lose fat from anywhere, and sticking to just one site can mean you miss seeing meaningful progress you’re making.[3] 
• Front, back, and side photographs. Take these about once a month, and be sure to stick to the same outfit, posture, and background so you’re comparing apples with apples. 

These methods aren’t perfect, but they’re accessible, easy to do, and fairly reliable at demonstrating your progress. 

Difference between fat loss and weight loss

To recap our understanding weight loss vs. fat loss so far: 

• Weight loss is when you reduce your overall body weight. 
• Fat loss is when you reduce your body fat percentage. 
• When you lose fat, you can lose weight at the same time. You can also maintain or gain weight. 
• When you lose weight, you may have lost water, muscle, fat, glycogen, or bone mass. 
• Losing water, muscle, glycogen, or bone mass does not make you healthier. 
• Losing fat (within a healthy body fat range) decreases your risk of chronic diseases and improves your metabolic health.

OK. So which one “should” you aim for? 

Should you aim to lose weight or fat?

Your goals are your goals. 

So check in with yourself. What do you want? 

If the number on the scale really means something to you, ask yourself why. Dig deeper into that. 

You might uncover something in the mix that looks like a desire to improve your health and wellbeing. For instance, maybe you want to:

• live a long life
• be able to run round with little ones or pets
• climb mountains
• be comfortable in your skin
• feel confident in your body
• have less joint pain (which can happen when body weight loads joints like knees and ankles)
• compete in a weight-classed sport (go champ!)

If that’s true, the actions that create fat loss (which we’ll come to shortly) might also be worth pursuing. Why? Because:

1. Focusing on behaviors rather than outcomes helps you build healthy habits.
2. Tracking fat loss and weight loss can help you stay motivated by showing you more than one type of progress. 
3. Chasing only a scale weight can make you do things which harm your body, like undernourish yourself or push too hard in the gym. 

How to lose fat and maintain or gain muscle

Whatever your goals, keeping (and increasing) your muscle and bone mass is also important. 

Losing muscle can lead to things like [4]:

• a slower metabolism
• fatigue
• being less mobile and active
• increased risk of injury

By contrast, having a healthy amount of muscle has many benefits, such as:

• regulating blood sugar levels
• maintaining healthy fat levels 
• controlling inflammation
• lower risk of chronic diseases like heart disease, kidney disease, and diabetes [5,6,7]

For long-term weight management, having more muscle is a winner. 

Muscle burns more calories at rest than fat does, meaning the more muscle you have, the more calories you burn for every single activity you do, from jumping rope to snuggling on the couch.[8]

So, what can you do to make sure your fat loss efforts don’t suck your muscle out along the way?

1. Try intermittent fasting

Intermittent fasting, an approach to body transformation that alternates periods of eating with periods of fasting, can be superb for both losing fat and preserving muscle.[9,10] 

When it comes to intermittent fasting for beginners, there are lots of options to try like intermittent fasting 16:8, or the 5:2 diet.

If you’re a little more experienced with intermittent fasting, alternate day fasting might appeal. 

(You might also have heard of water fasting and Eat Stop Eat but, to be frank, we’re not super keen on those for sustainable body change or great health.) 

If intermittent fasting sounds good to you, we’re here to support you on your journey. You can get going with our SIMPLE quiz! 

2. Shoot for a modest calorie reduction. 

You do need to eat fewer calories than you burn to lose weight. But if you go too hard too fast, your weight loss will be the water / glycogen / muscle loss kind — and your body will also fight back. 

With too high a calorie deficit, your body doesn’t get the fuel it needs. That makes it harder to exercise, sends your cravings into overdrive, and slows your metabolism, making you burn less calories overall.[11,12,13]

All round, not a great environment for fat loss or muscle gain to thrive. 

3. Focus on protein (and friends). 

A higher protein intake can help you to:

• hold onto — and build — more muscle 
• keep your metabolism fired up
• manage your cravings 
• lose more body fat

Protein can’t do all this alone, though. Make sure to also include smart carbohydrates, healthy fat, fruits and veggies, and calcium rich foods like dairy and tofu. 

These macronutrients work together to transform your body. Here’s how to meal plan for maximum results. SIMPLE’s here to help you stick to that meal plan, too, with our helpful food tracker to make sure you’re crushing that meal plan. Take our SIMPLE quiz and get started today!

4. Move some weight

Burning calories is essential for burning fat. Strength training burns extra calories both while you’re working out and after you’ve finished too. 

That’s excess post-exercise oxygen consumption (EPOC) — the increase in your metabolic rate following a strength training session — at work. 

But strength training also builds muscle and, as we’ve seen, more muscle makes your body burn more calories for every activity you undertake. It makes your metabolism faster and more efficient.  

Now, while keeping and/or building muscle is a key part of fat loss, it can potentially interfere with weight loss. 

If you’re burning fat and holding onto muscle, your weight may stay the same or drop less than you predict or hope. 

If you’re burning fat and gaining muscle, you may see the scale number increase. In fact, as you exercise more, your bone density increases, meaning even your bones can become heavier.[14]

But, while the scale may not be what you anticipate, you will also be getting healthier, stronger, and fitter. Your body will likely change shape. Your bones will get denser, protecting you from osteoporosis as you age, and your risk of conditions like diabetes and heart disease will drop. 

5. Get your heart pumping

Let’s not leave out cardio. Cardio + strength + nutrition = a powerful combination for muscle retention.[15] 

But do blend cardio into your workout mix with care. 

Yes, cardiovascular exercise like walking, running, cycling, and rowing is part of fat burning.[16] It burns calories and helps us manage our appetite.[17] 

However, too much of it can cause muscle loss, trigger cravings and hunger, and throw your energy in the trash so you move less overall (and lose your training mojo).  

If you need ideas on how to make both strength and cardio work for you without overdoing it, check out our how to burn fat article. 

Body composition and weight

Your body composition is made up of two main components:

• Fat mass: your subcutaneous and visceral body fat
• Fat-free mass: everything else, including water, muscle, bones, and organs, etc.

Here’s why this matters to our discussion of the difference between weight loss and fat loss. 

Muscle is denser than fat, so one pound of muscle takes up less space on your body than one pound of fat.[18] That means someone with more muscle and less fat will look different to someone with less muscle and more fat, but both people might weigh exactly the same. 

We saw earlier that bones can become heavier through regular exercise, and your body’s water content fluctuates through the day. 

It’s impossible to know how heavy or light your body will be when it settles at a weight it’s happy with, because there’s so much more to your body composition than you can influence. 

Put simply, a healthier body composition — i.e., more fat-free mass and less fat mass — doesn’t necessarily correlate to a lower weight. 

SIMPLE’s expert opinion and final thoughts 

Whether you want to lose weight or fat, focusing on the actions that lead to fat loss will give you the best of both worlds. 

Define how success looks to you beyond the scale. What else do you want? 

• To be a consistent exerciser? 
• To feel better in your clothes?
• To move more easily? 
• To look more toned or muscular?
• To have more energy?

Based on that, measure what matters: your exercise frequency, how your clothes fit, your ability to move, how your body looks to you, how energized you feel, and so on.

And from there, focus on what you can control: your actions. How about this as a first step: Try out our quiz

We’ll help you get clear and focused, find a good intermittent fasting protocol for you, and be right there with you to cheer you on as you chase your goals.

Frequently asked questions about fat loss vs. weight loss

Can I lose fat without losing weight?

Yes, you can lose fat without losing weight. If you gain muscle, for instance, this can mean you maintain or even increase your weight. 

Does fat loss take longer than weight loss?

Some weight loss can be pretty fast but, when it is, it’s usually water weight. If the weight we lose is fat, then fat loss doesn’t take longer than weight loss because they’re the same thing. 

What happens first, weight loss or fat loss? 

Usually what happens first is weight loss, because we often initially lose water and glycogen when we reduce calories. Losing weight like this tends to happen up front vs. losing fat, which is more of a slow burn. 

Which part of the body is the hardest to lose fat? 

The part of the body it is hardest to lose fat from will vary from person to person. It’s often the belly, but for some it can be thighs or arms. You can’t control this or spot reduce body fat, so relax and let your body do its thing.  

How long until weight loss is noticed? 

How long until weight loss is noticed will depend on what you’re doing to achieve it and how your body responds to that. It could be anything from a few days to a few weeks. 

Why do I look thinner but weigh more? 

You may look thinner but weigh more if you’ve lost body fat and gained muscle, because 1 lb of muscle takes up less space in the body than 1 lb of fat.

Written by Trey Reck

Medically reviewed by Josie Porter, RD

Published on | Updated on March 28, 2024