Daily Weight Changes: Why Does Your Weight Vary So Much?

Daily Weight Changes: Why Does Your Weight Vary So Much?

(Last Updated On: March 26, 2019)

Daily Weight Changes: Why Does Your Weight Vary So Much?

How often do you step on the scale? If you hop on every day, you’ll quickly discover your weight fluctuates, up to several pounds, from one weigh-in to the next. If you’re eating cleanly and working out, a sudden bump up in weight may raise concerns you’re moving in the wrong direction. People who weigh frequently sometimes become obsessed with the numbers on the scale in an unhealthy way.

The reality is daily weight changes often have nothing to do with an increase in body fat. Many factors, other than gaining body fat, can cause you to weigh more than you expected. That’s why fitness experts recommend weighing at the same time each day to control for some of these factors if you must weigh daily. Whether you SHOULD weigh every day is controversial. First, let’s look at what causes daily changes in weight.

Daily Weight Changes: Eating a Big Meal

The worst time to weigh is the day after a cheat meal. When you cheat, you eat more than usual and what you eat has weight. You probably also consumed more sodium, leading to water retention, and likely ate a meal higher in carbs. The carbs in the cheat meal replenished muscle and liver glycogen stores. Don’t forget – glycogen holds onto water – a lot of water. For every gram of glycogen you store, you hold on to 3 to 4 times that amount of water.

It’s not unusual to gain between 2 and 6 pounds after eating a large meal, mostly due to water retention and replenishment of glycogen stores. You’ll likely find your weight slowly comes down a day or two after a cheat meal as sodium and excess water are flushed out of your system.

Daily Weight Changes: Water Weight

As mentioned, eating a high-sodium diet causes fluid retention and temporary weight gain. Several other factors impact your body’s sodium balance and can lead to fluid retention and water weight gain. Many women experience fluid weight gain 7 days before a menstrual period. If you’re taking birth control pills or hormone therapy, they, too, can cause fluid retention.  In some cases, non-steroidal anti-inflammatory medications, which some people take for sore muscles and injuries, cause your body to hang onto fluid. Steroid medications, like prednisone, can do it too.

As counterintuitive as it might sound, the best way to deal with fluid retention is to drink more water. If you don’t, your body will work harder to hang onto water. Lay off the salt shaker and processed foods and eat whole foods rich in potassium. Potassium acts as a natural diuretic to help eliminate excess water weight. Eat more fruits and vegetables that are naturally high in potassium.

Daily Weight Changes: Constipation

When your bowels don’t move regularly, waste builds up in your intestinal tract and causes the scale to tip too high. Get your digestive tract into good working order by consuming more fiber and probiotic-rich foods. If you’re having persistent constipation along with other symptoms, see your doctor. Constipation can sometimes be a sign of an underactive thyroid, another cause of weight gain, or a problem with your colon. Your daily weight changes as much as three pounds just by having a bowel movement.

Daily Weight Changes: Should You Weigh Every Day?

If you weigh daily, do it as soon as you wake up AFTER using the bathroom. Even then, you may see fluctuation depending on where you are in your menstrual cycle, how much fluid you drank the day before, and how much sodium you consumed. Expect these fluctuations – they have nothing to do with your long-term progress.

What would be more concerning is if your weight STAYS up over multiple weigh-ins. Even then, if you’re weight training, some of the increase could be due to muscle gains. The only way to differentiate between fat gain and muscle gain is to track your body fat percentage.

Daily Weight Changes: Weighing Daily May Have Benefits

Despite the downsides of daily weighing, there are some potential benefits. A study carried out at VCU School of Medicine showed daily weigh-ins may help you better manage your weight long-term. In this study, 178 overweight or obese adults were assigned to calorie-restricted diets and an exercise plan. Over 18 months, those who weighed daily lost more weight, on average, than those who weighed less frequently.

A study carried out at the University of Minnesota involving 1,800 adults showed those who weighed themselves daily lost 12 pounds over a 2-year period while participants who weighed weekly lost only 6 pounds.

A number of studies show daily weigh-ins help with weight loss and weight loss maintenance – no surprise here. When you get daily feedback on your weight, you can react quickly before a small amount of weight gain turns into something less manageable. In fact, 11 out of 12 studies showed weighing daily led to greater weight loss.

So why are some nutritionists and trainers against weighing daily? Concerns are that weighing so often creates an unhealthy obsession with weight and fuels eating disorders. Most research doesn’t support this idea, although it could be a problem for people with a history of an eating disorder.

So, the question arises again: Should you weigh every day, once a week or not at all? If you’re the type of person who feels anxious or depressed when you’re up a few pounds, daily weigh-ins are probably not for you. But if you understand and accept the idea that weight fluctuates for reasons other than fat gain and aren’t going to beat yourself up when your weight goes up and down a few pounds from one day to the next, track your weight more closely.

Daily Weight Changes: Weight Isn’t the Only Marker for Health

An even better option is to focus on getting stronger and more physically fit and eating the healthiest diet you can and not let weight become your main focus. What’s most important is how you look and feel and how other markers for health are changing such as your blood pressure, heart rate, lipid profile, exercise tolerance, and strength. How your clothes fit is another indicator of whether you’re making progress. If they’re feeling looser, you’re moving in the right direction.

Even more important than body weight as an indicator of health is waist circumference. A waist circumference of above 35 inches in women is linked with greater risk for heart disease, type 2 diabetes, and higher mortality.

The Bottom Line?

It’s important to keep track of body weight, but don’t be a slave to the bathroom scale. Understand your weight will vary based on the factors already discussed. Most important is how you look and feel. Know where you stand but don’t become obsessed with a number.


Psychology Today. “Daily Weighing May Help Manage Your Weight”

International Journal of Behavioral Nutrition and Physical Activity 2008, 5:54  doi:10.1186/1479-5868-5-54.

Prevention. “How Often to Step on the Scale”


Related Articles By Cathe:

3 Reasons the Scale Says You’re Heavier that Have Nothing to Do with Body Fat

6 Common Causes of Water Weight Gain

What Happens to Your Body When You Eat a Cheat Meal?

Does Daily Weighing Help with Weight Loss?

4 Common Causes of Water Retention and Water Weight Gain

The Role Willpower Plays in Weight Loss and How You Can Develop Your “Weight Loss Muscle”


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