Estimated reading time: 6 minutes

Weight fluctuation is part and parcel of being human. If you weigh yourself after a big meal or when you’re retaining lots of water you’ll see a different number to if you weigh yourself after an early morning exercise session before you eat. And many of us see fluctuations in our weight over weeks or months too – maybe you put on some weight when it’s cold and you’re eating more than usual, or after a particularly busy festive season. 

And it isn’t just us everyday people either. Intentional weight fluctuation in the film industry is relatively standard. Jared Leto piled on an extra 67 pounds to resemble his character in the film Chapter 27. And Tom Hanks has followed extreme diets to lose weight for roles too. In these circumstances, actors have access to dieticians and physical trainers. They have experts on hand, and yet they still suffer. Leto suffered to such an extent from this weight gain that he sometimes required a wheelchair. 

These Hollywood situations may be extreme, but it begs the question of how much weight fluctuation is normal. When do you have to worry about the scale going up and down, and when is it just regular peaks and troughs?

With myriad factors affecting weight, including stress, exercise, and hormones, it’s helpful to understand the fine line between when weight fluctuation is healthy or a cause for concern. 

Jeans with tape measure around the belt hooks to show weight loss

Average weight fluctuation 

It’s perfectly normal for your weight to fluctuate by 1-2 kilograms or up to 4.4 pounds over a few days. 

Depending on your daily routine and when you weigh yourself, your weight can fluctuate to this extent in just one day. 

Some aspects of weight fluctuation are entirely out of your control. These aspects include your genetics, gender, and age. 

The good news is that you have some control over things that cause weight fluctuation. This control is over your exercise, diet, water, and alcohol consumption. 

The role of water on weight fluctuation 

When you are suitably hydrated, your body consists of 60 percent water

There are specific circumstances where your body stores water, causing your weight to increase. Some situations seem counterintuitive. For instance, if you consume a large quantity of water, your body may be more inclined to expel this. Whereas if you don’t consume adequate water, your body may retain water to avoid dehydration. This is the infamous water weight you’ve heard about. 

As well as dehydration, here are a few other circumstances when water may cause weight fluctuation. 

  • Excess sodium can lead to water retention. 
  • Food and drink consumed versus excreted impacts water retention. 
  • The sweat produced through exercise can result in reduced water retention. 
Low angle shot of woman's running shoes and flask of water

How dieting impacts weight fluctuation 

Crash diets are unhealthy and unsafe. They don’t work in the long term. Restricting calories can cause your body to go into panic mode. Your body doesn’t compute that you want to fit into that special outfit. Instead, your body associates the restricted calories with a catastrophe, such as war, and goes into survival mode. 

Excessive calorie restriction may provide initial weight loss, but these effects don’t last and can result in weight gain. Often, muscle mass reduces and fat increases. 

Fad diets can instigate a cycle of weight fluctuations. Not only is this frustrating for you, but it also has health implications. 

According to the Metabolic Research Centre, weight fluctuations through fad diets can result in: 

  • Long-term injury. 
  • Disordered eating.  

You can achieve long-term weight loss by eating in a safe calorie deficit, prioritizing a balanced diet, and increasing your exercise or moving more during the day in general.

When to worry about weight fluctuation

You can expect a certain amount of weight fluctuation. According to Healthline, if your weight fluctuates by more than 6 pounds in 6 months, it may be time to consult a specialist. 

Unintentional weight loss can indicate health issues, including: 

  • Mental health issues. 
  • Hyperthyroidism. 
  • Stress. 
  • Illness. 

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Unusual weight gain can also indicate health issues, including: 

  • Sleep issues. 
  • Heart problems. 
  • Kidney problems. 
  • Disease. 

Weight gain may be a side effect of some medications, so if you are on any medications, it may be wise to check the labels before you worry about weight changes. Bear in mind weight gain is normal during menstruation. Your body should correct this within a few days of menstruation. 

Remember, hormonal changes also impact weight changes. For instance, due to a change in hormones, menopausal women often put weight on. 

How to monitor your weight accurately 

The most accurate time to weigh yourself is in the morning after you go to the bathroom and before you eat or drink anything. Weighing yourself following nighttime sleep is the best time to obtain an accurate weight record. Sticking to the same time is best to avoid false weight fluctuation readings.

Remember to go easy on yourself. It is possible to slim down and put on weight due to changes in your body composition. While weight is one way to measure your body composition, another way is through how you feel about your reflection and how snug or lose your clothes feel on you. 

If you feel the scale isn’t helping, remember there are alternative ways to measure your wellness, health and progress.

Man's feet on set old, traditional weight scales with needle

Slow and steady for long-term results

Some amount of weight fluctuation throughout the day is perfectly normal. But if you find your weight fluctuating excessively, maybe it’s time to get to the bottom of this. Consistent calorie intake, exercise, and appropriate water consumption should help you find a steady weight. 

Remember, the different ages and stages of life affect weight fluctuations. Try not to compare your weight to a much younger version of yourself. Stay in the present and work with the body you’ve got. 

Words by Ali Hall