Weight loss vs fat loss - What's the difference?

"I need to lose weight". An often used term, but actually it's often used incorrectly. There's a huge difference between losing weight and burning fat.

Weight loss can be a combination of losing water weight, muscle mass or body fat, which is the one you actually want. You want to understand the difference? Then read on.

The big difference between weight loss and fat loss


Body weight is often used as an indicator, even though it's somewhat meaningless.

Basically, weight loss is a reduction of your overall body weight, based on the composition of your bones, organs, water retention, muscles and body fat. See, there's a lot more you can lose, before you reduce body fat.

Based on your level of fitness, this weight comes from:

  • Bones: 15% of your body weight
  • Organs: 10-15% of your body weight
  • Body fat: 10-30% of your body weight
  • Water: 10-25% of your body weight
  • Lean muscle tissue: 30-55% of your body weight

The thing is, weight loss can be pretty easy. Reduce the amount of carbs for one day or manipulate your water and sodium intake (carbs bind to water, so eating less carbs makes you lose water) and 4-6 lbs (2-3kg) are gone. However, this weight comes back as quickly as it goes. Losing water weight has nothing to do with losing fat.

The problem with weight loss

Losing water weight might lead to a slimmer appearance, but it's pretty easy to regain it in only a few hours. Therefore, the most accurate way of telling if you're on the right path with your diet, is by measuring your body fat percentage.

Same with low carb or keto diets, where you drop a hell of weight in the first few weeks. But as soon as you switch back to a higher carb intake afterwards, you'll definitely regain the weight. Why? Besides the (potential) fat loss, you stripped the body of glycogen and water weight. When you now introduce carbs back to your diet, you replenish your glycogen stores (which is not a bad thing btw!) and regain water, hence also weight.

Always think fat loss not weight loss. Two people with a similar height can weight the same, but have a completely different body fat percentage and therefore look completely different.

That's also why the BMI standard is obsolete. It doesn't take your muscle mass into account. Hence, you can have a pretty high BMI, but only because you carry a good amount of lean muscle mass.

Plus, lean muscle mass takes less space than body fat. So you can have a leaner and slimmer appearance, but a higher weight.

More muscle mass burns more body fat


Body fat is not only a lot less dense than muscle mass, it also burns less calories at rest.

Think about it. If you want to burn fat quickly, you have to increase your muscle mass. Focus on weightlifting, starting with compound exercises.

How our bodies use fat

Our bodies have two main sources of fuel: glucose and body fat. Glucose is stored by the liver in form of glycogen and released in the bloodstream to fuel the body.

When the body uses fat, lipase gets activated, that ignites fat cells to release triglycerides, which fat cells are made out of. When they get the signal to exit the fat cells, they enter the bloodstream to get broken down to be used for energy.

Now that the body has relieved fat cells, they begin to shrink. When fat tissue shrinks, so does your skin and you begin to look slimmer.

When is my weight loss due to a loss of water or muscle?

You want to know, when you're losing water or muscle instead of fat? It's hard to tell, since it's rarely 100% of a single thing.

Being on a fat loss diet, you'll mostly lose fat and water though, as long as your protein intake is high enough.

Muscle loss can also happen when your food intake is cut too drastically without proper exercise (crash diets, anyone?).

However, when being in a caloric deficit for several weeks you'll definitely lose some muscle mass regardless of training and protein intake. The goal is therefore to lose as little muscle mass as possible!

How can I promote fat loss instead of muscle loss?


Doing a crash diet might help you reach a certain number on the scale, but that's mostly due to the loss of water weight. After the crash diet, you will regain the water weight and eventually even more, since your metabolism adapted to the very low calorie intake.

First, when dieting, you want to eat as many calories as possible, while still being in a caloric deficit. Usually 10-20% less than what you actually burn. This way, you won't lose too much muscle mass right away. Deficit means fat loss! Meaning, it doesn't matter if you eat high carb, low carb, keto, paleo, vegan or only Snickers. However, it's much easier when you focus on nutrient-dense instead of calorie-dense foods.

A higher intake of protein will spare muscle on a fat loss diet, which means you'll not lose as much muscle on a cut as you would on a diet low in protein (your body will not only burn fat on a deficit, but muscle too!). Aim for roughly 2g per kg of body weight or 1g per pound of body weight per day.

You don't have to do any sport to lose weight. Again, caloric deficit. But, it's easier when you work out, because you can eat more (see our activity dropdown in the calculator) and you'll look better in the end.

Weight lifting will increase your muscle mass and therefore the calories you burn, even when you sleep. Cardio will only burn calories while you do it, plus you'll most likely burn muscle doing it as well. Especially on steady state cardio, like jogging for an hour. Yikes!

Ditch the damn scale!


Your weight says very little about whether you're moving in the right direction with your health or not. Furthermore, it tells nothing about your relationship to food, hormones, digestive health or inflammatory status. All of which are crucial parts of a weight loss & fitness journey.

Is it fat or is it muscle? The scale can't tell, because all it measures is your overall body weight. Even body fat scales are nonsense. One problem with them is that they are completely inaccurate. Many variables affect the results, including how hydrated you are, when you last ate and exercised, and even whether your feet are highly calloused or dirty, as well as the type and quality of the product itself.

Rather use the mirror to determine if you look leaner/better/more athletic than last week. Numbers aren't everything!

What to do instead

Here are some alternatives to measure your progress more accurately:

  • Take progress pics: To notice the change, start to take "before" and "after" pictures from different angles. Do them monthly to get an accurate comparison. Always use the same camera, angles and the same lighting. Don't fool yourself!
  • Measure body fat percentage: Not only is it necessary to figure out how many calories you have toeat, it's also a very good indicator of how lean you are - way better than the useless BMI. The reason why we recommend using pictures: it works and is good enough. If you are honest to yourself, you'll get close to your real percentage range. Plus it's free, quick and you don't need any equipment.

A bigger goal for your health is a combination of healthy eating habits, healthy stress levels, adequate sleep, enough movement, low body fat percentage and eating foods you actually enjoy!

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