Is weight fluctuation normal?

woman drinking water-weight fluctuation and water weight

woman drinking water-weight fluctuation and water weight

Is Weight Fluctuation Normal?

Day-to-day weight fluctuation is normal.

How often have you stepped on the scale expecting good news and instead were presented with a 2-pound weight gain?

You have been working out, eating in a calorie deficit, just to be smacked across the face by this bulls***t.

There are very few things in the world that are more frustrating than gaining weight when working hard to lose weight.

“How could this happen? How could I have gained 2 pounds overnight?”

Unfortunately, this weight fluctuation can lead people to unnecessarily lower their calories or add even more cardio. Doing this might be unsustainable and cause many to abandon their weight loss efforts altogether.

How much weight fluctuation is normal?

A daily weight fluctuation of 1 to 2% of our body is normal.

Why does weight fluctuate so much?

The most common cause of weight fluctuation is water retention.

Water retention occurs when there’s excess fluid buildup in the body.

Inflammation, salt intake, and stress are some examples that might cause water retention and day-to-day weight fluctuation.

Some of the main reasons why we retain water are:

Eating too many carbs.

Eating more carbs than usual can lead to water retention and day-to-day weight fluctuation.

Carbohydrates are stored mainly in the muscle cells and the liver in the form of glycogen. Each gram of glycogen holds at least 3 grams of water(1). So when you consider that an average person can store around 600 grams of glycogen(1), you can see how our bodies hold on to more water.

That is why you might see weight fluctuation the following day after a high-carb meal. 

It also explains why people on a low-carb, paleo, or keto diet lose so much weight in the first weeks. This happens because the reduction in carb intake leads to a decrease in glycogen stores and, therefore, a loss in water weight. (1)

You are eating too much salt.

Eating foods high in sodium can cause your body to retain more water.

Studies have shown that increasing our sodium intake leads to water retention. (1)(2)

According to the FDA, Americans eat an average of 3,400 mg of sodium per day. However, the Dietary Guidelines for Americans advise that we consume fewer than 2,300 mg of sodium per day. (1)

Although you might be tempted to “cool it” with the table salt, it is often processed foods and their high sodium content that is most responsible for water retention and weight fluctuation.

Restricting or eliminating some of these foods could help limit the amount of water of body retains.

Increasing your potassium levels could also help with water weight.

Potassium helps reduce water retention by reducing sodium levels and increasing urine production. (1)

The Institute of Medicine recommends we consume 4,700 mg of potassium per day. (1)

Eating foods high in potassium like:

  1. Pinto beans
  2. Sweet potatoes
  3. Whole-wheat bread and pasta
  4. Cooked spinach
  5. Tuna
  6. Cooked broccoli

Eating some of these foods could help you meet your daily potassium goal.

Another option to increase your potassium levels is with a supplement.


As if we didn’t have more to worry about, chronic stress can also cause water retention and weight fluctuation by increasing cortisol secretion. (10)

Cortisol levels rise in response to physical and emotional stress.

Yes, that includes exercise. That is one of the many reasons we need to allow our bodies to rest and recover when exercising.

With that being said, long-term stress can indeed sabotage your weight loss.

In a study by Kistenmacher et al., mental stress raised cortisol levels in all participants. It also resulted in 80% of “stress-eaters” eating 41% more food. (4)

Chronic stress can also cause us to skip the gym. (1)

Those who exercise regularly tend to deal better with stress and anxiety than those who don’t. (1)

It can also help you reduce work-related stress.

A 2019 study on 238 participants looked at the effects of 10-20 minute guided meditations on work-related stress.

The meditation group reported positive changes in well-being, anxiety, job strain, and perceptions of workplace social support than those who did not participate in the guided meditation. (5)


Chronic sleep deprivation can cause us to retain water.

The hypothalamic-pituitary-adrenal (HPA) axis plays an essential role in our body’s stress response and regulating the sleep-wake cycle.

2005 study found that an overly active HPA axis can disturb your sleep cycles, causing sleeping problems such as:

    • Insomnia
    • waking up during the night
    • less sleep time

Furthermore, researchers have found that sleep deprivation can cause our bodies to secrete more cortisol throughout the day(1) and remain elevated through the following evening. (1)

Ideas you can use to improve your sleep quality are:

Create a routine before bed, like taking a warm bath or reading a book.

Your bedroom should be quiet, as dark as possible, and on the cool side (~68℉). 

Avoid drinking caffeine 6 hours before bedtime can disrupt sleep. (3)

Menstrual cycle

Most women see a weight gain during their period. This weight fluctuation can be attributed to water retention. 

A 2015 study found that 92% of women suffer from water retention during their menstrual cycle, mainly the second phase of their cycle. (1)

Researchers found that water retention was predominantly found in these areas:

  • Face
  • Breast
  • Abdomen
  • Pubic area
  • Upper arms
  • Calves

A possible solution to water retention and weight fluctuation during the menstrual cycle is supplementing with magnesium oxide. A 1998 study showed that supplementing 200mg of magnesium oxide every day reduced water retention after two months. (1)


Some types of medications can cause water retention.

These include:

  • Nonsteroidal anti-inflammatory drugs like ibuprofen
  • Calcium channel blockers
  • Corticosteroids like prednisone
  • Some diabetes medications like pioglitazone and rosiglitazone

If you believe your medication is causing water retention, speak with your doctor about possible alternatives. 

Weight training

Starting a new workout routine or coming back from a long layoff can lead to water retention and weight fluctuation.

New exercises, especially when resistance training, can lead to micro-tears in our muscle fibers.

These micro-tears can cause inflammation, leading to water retention and a slight increase in weight.

There’s no need to worry. These micro-tears are completely normal. Make sure you rest, drink enough water and sleep between 7-9 hours per night.

Your body weight will go back to normal after a few days.


Some supplements can also cause water retention and weight fluctuation.

Creatine is naturally produced in the body from the amino acids glycine, methionine, and arginine.

It helps power the first ten seconds or so of activity.

Creatine causes water retention by pulling water into your muscle cells.

This cell hydration can help increase muscle strength and performance output and improve lean body mass and body composition. (2)(3)(4)

Extreme dieting

In the long term, going on very low calories can also lead to weight fluctuation due to water retention.

An example of extreme dieting can be seen in the “Minnesota Starvation Experiment.” In this study, thirty-six participants were put on an extreme diet, causing them to lose more than 25% of their body weight. 

One of the many side effects of this extreme diet was edema or water retention in the lower extremities and faces. When researchers slightly increased the participants’ calories, the water retention subsided. (1)

Although this might not fall into the category of day-to-day weight fluctuation, I believe it is essential to understand that dieting and exercise are a form of stress. And that extreme dieting and performing too much exercise have adverse effects on our bodies.

A general guideline is to lose between .5 and 1% of our body weight per week.

The Bottomline

Day-to-day weight fluctuation of 1-2% is normal and can be attributed to water retention. 

There are many reasons why we hold onto water weight, some of them being poor sleep and an increase in stress and sodium intake.

Luckily, water retention is only temporary, and you could expect your weight to back to normal in a few days.

Are you struggling to lose weight? “The complete fat loss guide” teaches you how to lose weight and how to keep the pounds from ever coming back.