Editor’s Note: This post was updated on October 17, 2018for accuracy and comprehensiveness. It was originally published on September 11, 2015

Losing weight is hard.  It requires working out regularly, making sure you get enough nutrients in your diet ( like protein). If you’re like most people, you want to see results that justify your hard work.  And that result, more often than not, has to do with seeing that number on the scale go steadily down. So you step on the scale every day because you need a reason to keep going.

Everything is fine until the unthinkable happens:  the scale stops going down. Or, after one “cheat day” you find yourself 8 pounds heavier and you think, “Oh no! Everything I’ve done for the past 2 weeks is for nothing!”  Repeat this a few times and before you know it, you’ve given up on working out and you’ve dumped your diet.

Sound familiar?

The truth is, you were probably making progress before you quit. Don’t give up.  You probably just got discouraged because you did what no one should ever do: you let the scale trick you.

Here are 5 reasons why you scale is a terrible tool for weight loss and how it can make you give up.

First and foremost…

1. You’re confusing “weight loss” with “fat loss”

It’s a safe bet to assume that when people want to lose weight, what they really want is fat loss.  The problem is, many people use the words “weight loss” and “fat loss” interchangeably, which are two separate concepts.

Losing overall weight isn’t hard – you’ll drop a few pounds of water weight if you sit in a sauna for a while. Fat loss is harder to achieve, depends on several factors, and it takes more time than you think to truly lose it.  Here are a couple key points about fat loss to consider:

  • When you lose weight, you lose more than just fat.  

Muscle and water (in addition to water weight) are two major components that make up your weight, and when you lose weight, you can lose some of each.  How much of each you lose depends in part on how much fat you have to lose when you start. Heavier people have more to lose than thin people, and they will lose more weight from fat than muscle than thin people.

  • You can drop weight but dropping actual fat takes time– more time than you think.  

Many people set fat loss goals for themselves that are unreasonable.  The truth is, without going on an unhealthy near-starvation diet, you can only expect to lose 1-2 pounds of fat per week at best.

Don’t expect to lose 10 pounds in a week, because even if you do, it’s not going to be all fat.  Losing muscle is not good for your health, and you will want to preserve it as much as you can.

But what about the people who do claim to lose 10 pounds in a week?  There are reasons for this, beginning with…

2. Your glycogen levels are changing, which can cause large weight swings in either direction

Glycogen is a short-term energy source that your body taps into when it needs immediate energy.  Although it is produced from many different types of foods, foods rich in carbohydrates like bread trigger glycogen production more than any other food source.  It’s a very good energy source, so much so that this is the major reason why marathon runners have “pasta parties” the day before the race: it’s to fuel up on glycogen!  You might also know this by another term: carb-loading.

In terms of your weight, however, glycogen has a very interesting attribute: 3 to 4 grams of water will bond to each gram of glycogen.  You always knew that diet played a big role in both fat and weight loss, but once you understand the role glycogen and water have with each other, a lot of things will make sense to you.  For example:

  • This is why people lose weight on carb-restricting diets like the Atkins diet

The Atkins diet and other diets similar to it (ketogenic, paleo, etc.) revolve around one major concept: restricting carbohydrates, and by extension, glycogen. Once your glycogen levels become depleted, there is less water for the glycogen to bond to. This is why many people who go on ketogenic-style diets appear to lose pounds very quickly: much of the initial weight loss is simply water.

  • This is why people believe they’ve “gained it all back” after cheating on their diet

Here’s a common situation that everyone has probably experienced at least once: after going on a strict diet (most likely low in carbs and high in protein) for a couple of weeks, you treat yourself to a weekend where you ate all the carbs that you missed so dearly.

Weighing yourself monday morning, you find that you’re 8 pounds heavier. Sad face. Good news: you didn’t waste any of your hard work!  It’s glycogen that’s fooling you and it’s mostly just water weight.

It’s deceptively easy to refuel yourself on carbohydrates and replenish your glycogen levels.  A typical endurance athlete, for example, requires around 500-600 g of carbohydrates a day to perform at optimal levels.

500-600 g of carbohydrates might sound like a lot to you at first, but consider that unless you actually are an athlete, your carbohydrate needs are a lot lower than you think.  Add this to the fact that:

Since many popular foods are so rich in carbs, it’s not very hard to refill your glycogen stores in a day if you aren’t watching your carb intake, or are choosing not to for a special occasion.

By refueling on carbs, you’re replenishing your glycogen levels, and water is binding to it.  So, you haven’t sabotaged your goals; you’ve probably put on water weight. Watch how fast you will lose body water again if you reduce your carbohydrate intake.

However, glycogen isn’t the only molecule that can retain water.  There are others that influence your water and your weight, which leads to the next point…

3. You’re retaining water due to your salt intake

Salt (or more accurately, sodium) is everywhere and extremely hard to avoid.  It might not surprise you that a single patty cheeseburger contains over 500 mg of sodium (nearly a quarter of the daily recommended levels), but would you be surprised to know that the ranch dressing you’re putting in your salad contains over half that, as much as 270 mg? Or that a tablespoon of soy sauce that you’re using in your healthy, vegetable-only stir-fry has 879 mg of sodium?  Little surprise that the Mayo Clinic estimates that the average American consumes about 3,400 mg of sodium a day: close to double what’s recommended.

Sodium is linked with water retention, and it is the job of your kidneys to expel unneeded sodium out of your body.  Until your kidneys are able to do that, you will temporarily be holding onto extra water. If your daily water and sodium intake habits change from day to day, this can contribute to water retention, which will cause fluctuations in your daily weight.

So, if you were on a diet but flooded your body with more salt than you normally have, you can expect to see a temporary increase in weight.  It doesn’t mean that all your hard work is for nothing; it just means that you’re experiencing additional water weight because of the extra sodium in your body.

However, there are other factors other than diet that can lead to weight fluctuations including…

4. Your muscle gains are outweighing your fat loss

If you’re strength training as part of your strategy to reduce your body fat percentage, you’re doing something right!  Adding resistance training (or any type of strength training) to your fat/weight loss plan is a great way to protect and preserve muscle loss as you subtract fat from your frame.

However, if you’re new to weightlifting and you’re pushing yourself hard, you’re going to see the number on the scale go up!  Why?

This is because as you are losing fat, you are replacing that weight with muscle.  Your weight may not go down, but your body fat percentage will.

For example, let’s take a 117-pound woman and assume she has 38.6 pounds of fat mass, 78.4 pounds of Lean Body Mass, and 42.3 pounds Skeletal Muscle Mass.  That’s consistent with a body fat percentage of 33%, which is slightly over the normal range for women (which ends at 28%).

Now let’s take that same woman and say that she begins a comprehensive fat burning program that includes dietary changes, cardio, and strength training.  After 3 months, she now has 32.6 pounds of fat mass, 84.4 pounds of lean body mass due to a 6-pound increase in SMM. She still weighs 117 pounds, but now her body fat percentage is 27.8% – a big drop from her previous result of 33%, which brings her into the normal/healthy range.

You may be thinking right now “Oh, but this woman would know that her efforts were successful because she should look different and feel different with 6 pounds of fat loss and a 6 pound gain in skeletal muscle mass.”  But remember, it took her three months to get there.

Do you think she would looked and felt different right away, with only a scale to measure her progress?  Without measuring your body composition, would she have known if that she was making any progress in skeletal muscle mass gain or fat loss after, say, one month?  6 weeks?

You can imagine the frustration she could have felt by not seeing the scale move at all. She would probably give up before she reached the three month mark. This is why measuring body composition is so important.

These first four all point to one unifying, very important reason why you shouldn’t weigh yourself every day, which is…

5. You’re weighing yourself at different times of the day, under different conditions

If you’re weighing yourself whenever you feel like it without being consistent in terms of what time you weigh and what you’ve done during the day up to that point, the scale is going to mislead you every single time.

Generally, people’s weight increases during the day due to the food and drinks they consume.  Food and drinks also produce waste, which can also lead to additional weight gain throughout the day.  Naturally, this weight gain is temporary, but if you weighed yourself in the morning on an empty stomach, and then without thinking weighed yourself 5 days later in the middle of the day, you can’t compare those weights against each other.

Also, if your diet has changed in between your weigh-ins, that can cause significant weight changes.  Did you eat an unusually large amount of carbs the day before?  You could potentially see very large swings in your weight. But if you remember how glycogen bonds with water, this won’t bother you anymore because you’ll understand that it’s just water weight.

Did you just finish exercising?  You probably lost some water, leading to temporary weight loss.  Were you drinking water while you were working out? Your muscle cells may have absorbed some of it, causing your weight to respond accordingly. If you are going to rely on the scale, make sure you weigh yourself under similar conditions everytime.

Don’t let the scale trick you!

There are so many things that can affect your weight, so you should never get into the habit of weighing yourself every day.  So if not that, what should you be doing?

  • Look for consistent, steady, and gradual changes in your weight every 2 – 4 weeks

As difficult as it sounds, if you are using just a scale to determine your progress, you have to space out your weigh-ins.  If you still aren’t seeing weight changes in that period of time, you need to take another look at your diet and exercise plans and potentially make some adjustments.

  • Get your body composition analyzed and track your body fat percentage

Because your weight is made up of many different elements and can fluctuate for so many different reasons, assessing your weight by tracking your body composition is a much better way to determine how you’re meeting your goals.

Don’t let the scale trick you!  If you diet and exercise properly with enough patience and determination, you will reach your goals.