We all want to make constant progress towards our goals – it’s one of the most powerful motivators. And that’s why we often measure our progress on a regular, often daily basis.

In our efforts to achieve our dream physique, everyone is eager to keep their weight loss moving in the right direction, which we track with regular weigh-ins. This may be weekly or even daily for the more, ahem, ‘committed’ among us.

Daily checks

Daily weigh-ins can be beneficial, but only if used for the right reasons, like tracking trends over time to help you make associations with behaviours or eating habits that can inform your diet and exercise plans.

If you follow this approach, it is important to ensure that you take note of all the factors that may relate to variations in weight, otherwise, the process is meaningless and somewhat neurotic.

Let sanity prevail

Daily checks are not generally prescribed practice by health and fitness professionals, mainly due to the variability in our weight throughout the day. The truth, though, is that most of us do it anyway – it’s human nature.

To ensure you maintain your sanity each time you step on the scale, it’s worth keeping in mind that your weight fluctuates throughout the day, sometimes by as much as a few kilograms. This can be seriously disheartening, even to the most optimistic of dieters.

Factors that fluctuate your weight daily

So, if you’re on the more obsessive side and plan to weigh yourself more than once a month, here are a few factors to consider when it comes to daily weight fluctuations:


The food you eat has mass, even after it has been chewed, swallowed and digested. Whether it’s in your stomach, intestines or your bowel (read more below), having food in your system will cause fluctuations in weight. Food allergies or intolerances can also cause bloating and water retention due to the inflammatory response of the gut.


If you’re getting your recommended 2-3 litres of water a day then your weight could shift by 2-3kg in a day due to your hydration levels alone. A healthy bladder can also hold up to 473ml of urine, which is equivalent to almost half a kilo. Add in all the extra ingested and stored liquid in your body and you start to understand how wild shifts in weight can occur from one hour to the next.

Bathroom visits:

Urinating or having a bowel movement will obviously change your weight, for all the reasons already mentioned. Conversely, if you’ve been constipated for a few days then it is likely you’re a bit heavier than usual.


Certain types of exercise can affect your weight. In general, you’re likely to weigh a few grams less after a tough session due to water loss through sweat. This effect will be amplified if you train in hot and humid conditions.

Water retention:

Certain foods can actually cause you to hold on to more weight than others. High-carb meals, for example, can have an effect on our weight of up to 500g as our bodies store more glycogen. Also, foods that contain lots of salt (sodium) can cause water retention due to changes in the concentrations of minerals and the release of hormones that control water balance.

Water loss:

Diuretics are substances that cause the body to expel water. They can be found in everyday foods and drinks or in weight-loss supplements. It is therefore important to consider how these substances may affect your weight during weigh-ins if you are consuming them.


Changes in the balance of specific hormones that relate to a woman’s menstrual cycle can cause some degree of water retention which may affect weight.

Weigh-in guidelines

  • Start by weighing yourself on the same day and at the same time every week (or the same time every day) for consistency.
  • The most preferable time is first thing in the morning after using the bathroom, without any clothes on.
  • Always use the same scale.
  • Make sure you adjust the calibration before getting on if more than one person uses it to ensure greater accuracy.

When to worry

If your weight remains elevated for five days or more then you should consider making adjustments to your diet and lifestyle. Also, if you note an upward trend or stagnation over a period of time then you need to make a change to your exercise and eating plans.