How Often Should You Weigh Yourself?

How Often should I weigh myself

By: Tom Franclemont | Macros Inc. Coach

The Forces of Attraction

How frequently do you jump on the scale?  

Daily, weekly, maybe only monthly?  

Or perhaps you think it’s best to ditch the scale altogether.  Before you do that, let’s discuss what the scale does and how to make it a useful tool for reaching your goals.

It’s important to remember that a scale is an instrument for measuring weight, not mass.  What is the difference?  Gravity! 

Your body contains a certain amount of mass and that mass would be unchanged whether you were measuring it here on Earth, on the moon, or on another planet.  However, the scale is measuring your weight, which is the relative heaviness of that mass with the forces of gravity acting upon it.

The Key Influencer

Ok, why the lecture on mass versus weight? Well…many people are interested in weight loss, but since decreasing weight requires either reducing gravity or reducing mass, we actually are seeking to lose mass.  

Not all of the mass in our body is mass that we want to lose though.  Your body mass includes a combination of your organs, bones, muscle tissue, fat tissue, the contents of your digestive tract, bodily fluids, and more.  All of these are represented by the number you see on the scale.

One of the components that has the largest impact on the scale is water weight.  Have you ever lifted up a gallon of water?  It isn’t light.  For our friends using the metric system, it’s an easy calculation.  One gallon of water is equivalent to 3.785 liters and for water, 1 liter of volume weighs 1 kilogram, so 3.785L = 3.785 kg.  Putting that into imperial measurements, 1 gallon of water weighs approximately 8.3 lbs.

Why does that matter so much?  Water composes about 60-65% of an adult male’s body weight and about 50-55% for an adult female (1).  When you realize that a 200 lb adult male has roughly 14-15 gallons of water in his cells and tissues at any given time, then you can see why water weight is such a big deal.

That water in your body can fluctuate a great deal based on a number of factors, such as hydration levels, sodium intake, carbohydrate intake, and hormones just to name a few.  While the amount of fat mass or muscle mass that can be lost or gained in a 24 hour period is very small, the amount of water in your body can change significantly from day-to-day.  With more than half of your weight coming from water, that change is going to be very noticeable on the scale.

Trending Matters

Considering that fluctuations in body water have such a huge impact on the scale from day to day, you might be thinking now that weighing yourself frequently is pointless.  But in reality, the more points the better.  The best way to get useful information about your body mass is to consistently collect data to look for patterns and an overall trend in the desired direction.

Even though there are many factors that influence your water weight from day to day, keeping a consistent routine of checking your weight first thing each morning after using the bathroom is the best way to control many of the variables responsible for fluctuations.  This is the time of day when you will have the lowest amount of food and water in your system and being included in the measurement of how much gravitational pull the Earth is exerting on your total body mass.

If you only use the scale once a week or even less, then you are getting a limited amount of information and it is much more difficult to decipher what is happening.  However, when you weigh yourself daily, you can more easily spot days where your water weight is much higher or lower than normal.  Think about putting together a jigsaw puzzle.  Individual pieces don’t show you much on their own.  But with more and more pieces added in, you can see the picture start to come together.

What about those fancy scales that claim to be able to measure the composition of your body mass and let you know exactly what type of mass you are losing?  Sorry, they are not precise enough to measure the small changes that occur from day to day (they can be off by +/- 5-7%).  The method that is used to estimate your body mass composition (the speed of an electrical impulse moving through your tissues) is influenced by your hydration level just like your weight is and often the scale falsely interprets changes in water as changes in fat mass (2).  If your goal is fat loss, you are better off looking for a downward trend in your average weekly weight as a sign of a reduction in your fat mass.

Keeping Track Keeps You on Track

Not only does a larger pool of data points give you more reliable information about changes in your body mass, but weighing yourself on a daily basis improves adherence to a caloric deficit and produces greater fat loss results when compared to less frequent weighing (3).  Frequent monitoring of progress increases your awareness of how your choices are determining your results.

But, that also doesn’t mean that the hopping on the scale should be the only method you use to check your progress.  On the contrary, the scale should be one of many tools that are utilized.  Other methods are tracking body measurements, taking photos, being aware of changes in the fit of your clothes, and most importantly, what the mirror shows you.

The scale happens to be the method that gives us the most immediate feedback though, so while your ultimate goal should be focused on what the mirror shows rather than the number that the scale says, the data that we can collect from the scale is a key piece of getting those results.