When starting your weight loss journey, it may be instinctive for you to jump on the scale on a daily basis and expect the scale to give you a lower reading each time. If you do not get the reading you were hoping for, you may be lured to believe that your weight is not going down and instead going up because you are gaining body fat. However, it is completely normal for body weight fluctuation to occur. It’s fairly self-explanatory, however body weight fluctuation refers to the loss and gain of weight continuously over the day. In fact, body weight for an adult may fluctuate substantially by upto 5-6 pounds over the course of a day.

It is important to differentiate between normal body weight fluctuation and true body weight loss or gain. The reading you see on the scale is just one piece of data, which does not necessarily provide an accurate reflection of whether you're losing weight. Just because the reading on the scale gets higher or lower from day-to-day doesn’t mean that you aren’t on course towards your longer term weight loss goal.

So, why does this weight fluctuation occur? It mostly boils down to the water content of your body because of what and when you eat and drink, exercise, and even the menstrual cycle. Here, find explanations as to how these factors can cause an increase or decrease on the scale.

Sodium and Water Retention

Sodium is an essential nutrient for the body, however eating too much salt can result in excess sodium being retained by your body, leading to increased fluid retention in your body (1). This may cause a bloating of the belly and an increase in body weight. Even if you don’t add much table salt to your foods, sodium may be unexpectedly found in large amounts in foods such as cold cuts of meat and frozen ready meals. 

Glycogen Storage from Carbohydrates

Glycogen is the main storage form of carbohydrate, found in your muscle and liver. Upon consumption of carbohydrate, your body stores what it can of glycogen. Glycogen is stored with a considerable amount of water: every 1 gram of glycogen is bound to at least 3 grams of water (2). So, if you are consuming carbohydrates and they are not immediately being used, the water content of your body will increase. While this isn’t the same as water retention, your body weight is going to go up, nonetheless. During exercise, when your glycogen stores are being used more, the opposite will occur.

Food and Drink Weight

Regardless of their calorie content, foods and drinks all carry a weight to them and therefore, of course, will cause your weight to be increased slightly while the food is being digested and processed in your body. When you think about it, the food you consume over a day could weigh up to a few pounds in total. The water from food and drinks can cause your weight to be increased as well.


Water is the major component of your body, as around 60% of your body weight is made up of water (3). So, as you might expect, hydration naturally can influence the number you see on the scale. Indeed, staying well-hydrated is beneficial regardless of what your goal is. However, a sudden drastic increase in your water intake might actually result in your weight on the scale becoming slightly increased. And vice versa. When a lot of water is lost from the body, whether it’s because you didn’t drink much fluid one day, or you did a particularly strenuous workout and sweated a lot; this will cause the number on the scale to go down, which may give the false impression that you have lost a lot more weight from body fat than you actually have. 

Menstrual Cycle

For the women out there, it is normal for your menstrual cycle to cause your body to retain more water around five days before menstruation, which can cause a bloated feeling and possibly lead to weight gain of a few pounds. This weight gain is mainly due to hormonal changes. Levels of the hormones estrogen and progesterone peak in the days leading up to your period, which can cause fluid to be drawn from your blood vessels into your bodily tissues (4). However, this weight gain should only be temporary and your daily weight will return back to normal within a few days of beginning your period. 

Best practice when weighing yourself

It’s essential that you keep a consistent routine in order to accurately determine and track your true bodyweight. Here is a simple but effective step-by-step guide to measuring your bodyweight from week-to-week: 

  1. Weigh yourself on a weekly basis. If you’re weighing yourself to monitor progress, you may feel inclined to weigh yourself everyday, however try to avoid this. The water content of the body fluctuates over the course of a day (5), therefore body weight can vary substantially from day-to-day and often give an inaccurate result which can make you feel like you are not making any progress. Weighing yourself just once a week will provide you with a more accurate long term picture.  
  1. Using a scale correctly. Weigh yourself using a scale that is calibrated correctly, and use the same scale every time to ensure you receive an accurate result. 
  1. Weigh yourself at the same time of day. Make a conscious effort to weigh yourself at a consistent time of day. It is best that you make it part of your morning ritual by weighing yourself first thing in the morning once you have used the bathroom, and before drinking any fluid or eating a meal. This is because morning weighing allows for sufficient time for food eaten on the prior day to be fully digested and processed. 
  1. Weigh yourself wearing the same level of clothing. Keep your level of clothing consistent each time you weigh. The weight of different clothes can fluctuate, and therefore influence the result on the scale, independent of how much body weight you have lost or gained. Try to weigh yourself wearing as minimal clothing as possible - without clothes or with only underwear. 
  1. Incorporate other measures. Do not solely rely on the scale. Use this in combination with the BMI CALCULATOR and BODY FAT RATIO, as well as your own visual observation to gain a fuller picture of your overall progress. 

So, the take home message? 

Do not get too tied up in what the scale says from one day to the next, even if it was not what you were hoping for. It is normal for your body weight to fluctuate back and forth from day-to-day. Instead, keep to your plan and focus on the progress you are making over a longer period of time. Weigh yourself on a weekly basis and keep all variables consistent to ensure you are getting the most accurate reading possible. However, remember that the reading on the scale is only one piece of data and does not give the whole picture.

And lastly, but most importantly, enjoy the journey!



  1. Rakova, N., Kitada, K., Lerchl, K., Dahlmann, A., Birukov, A., Daub, S., Kopp, C., Pedchenko, T., Zhang, Y., Beck, L., Johannes, B., Marton, A., Müller, D., Rauh, M., Luft, F. & Titze, J. (2017) Increased salt consumption induces body water conservation and decreases fluid intake. Journal of Clinical Investigation, 127 (5), pp.1932-1943.
  1. Fernández-Elías, V., Ortega, J., Nelson, R. & Mora-Rodriguez, R. (2015) Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. European Journal of Applied Physiology, 115 (9), pp.1919-1926.
  1. Jéquier, E. & Constant, F. (2010) Water as an essential nutrient: the physiological basis of hydration. European journal of clinical nutrition, 64 (2), pp.115–123. 
  1. Stachenfeld, N. (2008) Sex Hormone Effects on Body Fluid Regulation. Exercise and Sport Sciences Reviews, 36 (3), pp.152-159.
  1. Armstrong, L. & Johnson, E. (2018) Water Intake, Water Balance, and the Elusive Daily Water Requirement. Nutrients, 10 (12), p.1928.



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