Blog Weight Loss Why Does My Weight Fluctuate 10 Lbs In A Day? 8 Reasons Why!

Why Does My Weight Fluctuate 10 Lbs In A Day? 8 Reasons Why!

Surprisingly, your weight is different throughout the day, but contrary to what many people think, daily weight fluctuation is normal. Why does my weight fluctuate 10 lbs in a day? There are a couple of reasons for such a fluctuation. Read on to learn more about how your weight fluctuates in a day and the reasons behind it. 

Why Does My Weight Fluctuate 10 Lbs in a Day?

If you just started watching your weight, you’ll notice that you have different results throughout the day whenever you weigh yourself. Sometimes the numbers are high and sometimes they’re what you expect to see. Here’s why the scale tips to both extremes throughout the day:

Water Retention

Water retention is one of the major culprits of daily weight fluctuation. Here are some significant causes of water retention (2):

High Sodium Consumption

Sodium, or salt, is crucial in our bodies as it helps regulate blood pressure, transport nutrients, and balance water levels in the body. However, too much of it makes you retain more fluids, which leads to an increase in the number you see on the scale (9). 


It’s important to drink enough water every day to avoid getting dehydrated. If you don’t drink enough water, your body stores water to avoid dehydration (6). As a consequence, you retain water, which may see your weight increase throughout the day, depending on your water consumption  (12). 

Your Diet

Your weight is also highly influenced by what you eat throughout the day. Your energy balances between what you eat and what you burn, affecting your weight over time. If you eat more than your body is burning, you’re likely to gain weight(8). 

Remember that weight loss is not easy. To lose one pound, the Mayo Clinic suggests that you’ll need to consume around 500 fewer calories each day for a week and/or burn these extra calories through exercise (2). Contrary to what you may think, this is not easy. 

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To avoid weight gain caused by your diet, you should talk to your registered dietitian to develop a meal plan that can help you maintain a healthy weight. Similarly, these professionals can also help you craft a weight loss diet plan if your goal is to lose weight.

Although there are many such meal plans online, we don’t advise you to start them without seeking professional help. 

why does my weight fluctuate 10 lbs in a day  

How You Weigh Yourself

The manner in which you weigh yourself may also lead to weight fluctuation throughout the day. There are several factors you must consider when weighing yourself, including your outfit, weight distribution on your feet, and where you place your scale (8).

Firstly, you should always place your scale on a hard surface, preferably the same surface every time. Also, when you weigh yourself, dress in light clothing and do the same every time you step on the scale. In addition, stand on both feet and make sure your weight is evenly distributed on both feet. 

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When You Weigh Yourself

In addition to how you weigh yourself, the time of day when you weigh yourself also accounts for the weight fluctuation. You’ll always get different results when you weigh yourself in the morning, afternoon, and evening.

Experts suggest you weigh yourself in the morning for the most accurate result (8). This is because at this time, you probably haven’t had anything to eat or drink. However, during the day, your scale will change after you eat and drink. So, if you always weigh yourself first thing in the morning, you’ll be able to more accurately identify trends, such as weight loss or gain over time. 

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Frequency of Your Bathroom Breaks

Believe it or not, your weight fluctuation is also affected by the number of times you visit the bathroom. If you eat a big meal and then weigh yourself, you may weigh more. This is caused by the fecal weight of the food waste you haven’t yet excreted (8).

Similarly, if you drink a lot of fluid, you’ll see increased weight. This is due to urine buildup. On the other hand, if you just emptied your bladder or bowels or have lost fluid due to diarrhea or vomiting and weigh yourself, you’ll see a lower number (8).


Exercising is essential as it reduces the risk of various conditions, improves overall health, and promotes weight loss. According to WebMD, some athletes are reported to drop 6% to 10% of their body weight after a workout due to the loss of fluid from sweating (8). This will be influenced by the intensity of your workout and the heat and humidity of your environment. 


There are several medications that can cause weight fluctuation, including:


One of the side effects of antidepressants is weight gain. You may experience weight gain after taking these medications for a while (10). Don’t stop this drug treatment if you suspect it’s responsible for your weight gain. Instead, talk to your doctor and tell them your concerns. They may recommend another drug alternative or other strategies to counter the negative effects. 

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why does my weight fluctuate 10 lbs in a day  


Some anti-inflammatory steroid medications such as prednisone result in weight gain (5). They tend to cause water retention, which results in water weight. Similarly, they also increase your appetite, making you consume more calories.

Despite this effect, experts don’t advise you to suddenly stop taking steroids if you’ve been taking them. This may lead to more severe problems, which is why you need to check with your doctor first.

Antipsychotic Drugs

These are medications that are used to treat psychiatric mental disorders such as bipolar disorder and schizophrenia (4). They may stimulate appetite, which makes you eat more food, and possibly consume more calories than required. Again, don’t stop your medication without talking to your doctor.

Birth Control Pills

There is a common belief among women that birth control pills cause weight gain. Before you blame the pill, WebMD notes that these drugs are not proven to cause long-term weight gain (10). However, some women may experience short-term weight gain due to fluid retention. Talk to your doctor if you’re concerned about your birth control pills resulting in weight gain.

Other drugs that may result in weight gain include medications that are used to treat diabetes, migraines, high blood pressure, and seizures (10). 

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Various Health Conditions

Some health conditions can also result in unexpected weight change and may suppress your appetite, while others might lead to water retention. Some of these conditions are:

Polycystic Ovary Syndrome (PCOS)

One of the many health conditions that results in female weight gain is PCOS. This is a hormonal problem among women of childbearing age where many small cysts grow on their ovaries (10).

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The condition leads to hormonal imbalances, which have several side effects such as weight gain, irregular menstruation cycles, hair loss, excessive hair on the chest, back, or abdomen, and acne (11). 

Unfortunately, there is no cure for this condition. However, doctors recommend women with PCOS to adopt lifestyle changes such as exercising and eating a healthy diet to ease the symptoms (11).


Hypothyroidism is a condition where your thyroid gland doesn’t produce enough thyroid hormone. If your thyroid doesn’t make enough thyroid hormone, you’ll feel weak, tired, cold, and end up gaining weight (10).

Similarly, WebMD acknowledges that your metabolism slows down, which means you’re burning calories at a slower rate than usual(1). A slow metabolism results in weight gain as you’re burning fewer calories than you consume. The only way you can reverse weight gain caused by hypothyroidism is to get treated for it. 

Kidney Problems

Sudden weight gain may reflect kidney problems if accompanied by other symptoms of kidney disease. If your kidneys are not operating efficiently, your body may retain water, which contributes to weight gain. 

Kidney problems can lead to water retention as the kidneys are responsible for removing fluids and excess water from the body (11) (12). Other symptoms you should watch for that indicate kidney problems include swelling of the hands and feet, fatigue and weakness, more or less urinating, nausea or vomiting, loss of appetite, muscle cramps, and dry, itchy skin (3).

Ovarian Cancer

Sudden and unexplained weight gain and bloating could be attributed to ovarian cancer (11). However, if this is the case, it will be accompanied by other symptoms such as sleeping difficulties, pelvis or abdomen pain, frequent urge to urinate, indigestion, unusual menstrual cycle, and loss of appetite (11).

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Cushing’s Syndrome

Cushing’s syndrome is another condition that leads to weight gain, particularly in the face, abdomen, upper back, and neck. The condition occurs when your body produces too much cortisol over an extensive duration (4).

Cortisol is the hormone that offers your body the ability to respond to stress. It is incredibly rare to develop this disease without an external trigger. However, it’s a major side effect of taking glucocorticoids. These are drugs that are used to treat asthma, systemic lupus erythematosus, and rheumatoid arthritis (5).

When to See a Doctor

Some causes of weight loss or weight gain are not alarming. Your weight will naturally vary throughout the day, and weight fluctuations are affected by how and when you weigh yourself. In such cases, there’s no need to see a doctor. All you need to do is re-adjust and learn when and how to weigh yourself for accurate results (1).

However, you should contact your doctor if you experience rapid and unintentional weight changes without any obvious cause. They will conduct a physical examination and possibly blood tests to determine if there is an underlying health condition that’s causing the weight changes.

Read more: Counting Macros for Weight Loss: Pros, Cons, and How-To (A Beginner’s Guide)

why does my weight fluctuate 10 lbs in a day  


  • Is it normal to gain and lose 10 pounds in a day?

It’s not normal for most people to gain or lose 10 pounds in a day. In fact, such rapid changes in weight can be detrimental to your health and may be a sign of an underlying medical condition. While our bodies can fluctuate in weight by a few pounds due to water retention or digestion, gaining or losing 10 pounds in a day is not typical.

It’s normal to see gradual weight changes over time, usually within a range of 1-2 pounds per week. This is considered to be a healthy and sustainable rate of weight loss or gain (7). Rapid weight fluctuations can put stress on your organs, disrupt hormone levels, and even affect your mental health.

If you find yourself experiencing such drastic changes in weight, it’s important to consult a healthcare provider to rule out any underlying health issues. They can also help you develop a safe and sustainable plan for managing your weight.

  • Does 10-pound weight gain show on the face?

10-pound weight gain can definitely show on your face. Facial appearance is closely linked to overall body composition, and any significant changes in weight can affect the way you look. When you gain weight, particularly in the form of fat, it tends to accumulate all over your body, including the face.

This added fat can lead to puffiness and bloating in the face, which makes it appear rounder and fuller. Furthermore, weight gain can also affect the distribution of fat in the face, causing changes in cheekbone definition and jawline appearance. So even though a 10-pound gain may not seem like much in terms of overall body weight, it can definitely have an impact on your facial features.

At the same time, water weight and bloating can also contribute to facial changes, particularly due to medical conditions that cause fluid retention (12). This may cause temporary swelling or puffiness in the face, which can make it appear slightly larger than usual. If you’re experiencing increased swelling due to fluid retention, you should talk to your healthcare provider.

We have tips for resolving this in our blog: How to Lose Water Weight.

  • How much weight is it normal to gain overnight?

It’s normal to see a 1-2 pound change in weight overnight due to fluctuations in water retention and digestion (12). However, anything significantly beyond this range may indicate a larger issue at play.

For example, gaining 5 pounds overnight can be a sign of fluid retention, which could be caused by factors such as consuming too much salt or dehydration (12). At the same time, losing several pounds overnight may be a sign of dehydration, excessive sweating, or a gastrointestinal illness.

Weight can naturally fluctuate throughout the day and it’s not uncommon to see these fluctuations reflected on the scale. However, significant changes in weight overnight should not be dismissed and may warrant further investigation from a medical professional.

Our blog, How to Get Rid of Water Retention Overnight, has tips for managing water weight and bloating.

  • Can you gain 10 lbs of water weight in a day?

No, you’re not likely to gain 10 pounds of water weight in a day. Your body can only retain so much water before it reaches a state of equilibrium and eliminates the excess through urination or sweating. 

Excess fluid retention may be caused by certain medical conditions such as heart or kidney disease, or by external factors such as consuming too much salt or taking certain medications (12). However, even in these cases, it would be highly unlikely to see a 10-pound increase in water weight in a day. Talk to your healthcare provider about how much weight fluctuation from water retention you should expect, and when you should seek medical attention.

The Bottom Line

Why does my weight fluctuate 10 lbs in a day? There are several reasons for these fluctuations, ranging from the medications you’re taking to when and how you weigh yourself, your dietary patterns, existing medical conditions, water retention, and the frequency of your bathroom breaks.


This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. 15 Things That Slow Your Metabolism (2023,
  2. Counting calories: Get back to weight-loss basics (2020,
  3. Chronic kidney disease (2023,
  4. Cushing syndrome (2023,
  5. Drugs That Affect Body Weight, Body Fat Distribution, and Metabolism (2019,
  6. How much does weight fluctuate? (2020,
  7. Losing Weight (2023,
  8. Reasons Your Weight Changes Throughout the Day (2019,
  9. Salt and Water Retention (n,d,
  10. Surprising Reasons You’re Gaining Weight (2020,
  11. What causes rapid weight gain? (2019,
  12. What to know about water retention (2022,
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