Four Reasons Your Weight is Fluctuating from Day to Day

Most people have experienced the frustration of stepping on the scale and seeing their weight fluctuate, even when they think they are eating and exercising consistently.

There are a number of factors that can contribute to weight fluctuations, including hormones, metabolism, water retention, and bowel movements.

  • Water retention can cause the body to temporarily gain weight. This is often caused by medications, dehydration, or salty foods.
  • Metabolism. Some people naturally have a faster metabolism than others, which can cause them to lose weight even when they are not actively trying to diet or exercising at home.
  • Hormones. For women, hormonal changes can cause the body to retain water and bloat, leading to a temporary increase in weight. Metabolism also plays a role in weight fluctuations.
  • Bowel movements. Finally, bowel movements can also affect weight. If you haven’t had a bowel movement in a while, your body may hold on to water and bloat, leading to an increase on the scale.

Let’s take a closer look at each of these, and see what you can do about it.

Why Does My Weight Fluctuate from One Day to Another?

Why does my weight fluctuate while I’m trying to lose weight and make healthier choices? You are not alone. This is a popular question among most dieters. In fact, watching the scales fluctuate becomes a challenge for many people to overcome and stay on their diet.

You probably know by now that striving for 1-2 pounds of weight loss a week is a good goal. The trouble is, with your weight fluctuating so much, it’s frustrating, and difficult to know if you’re losing weight or not.

When you’re trying to lose weight, get fit, and be healthier, the number on the scale isn’t always the best gauge for measuring your progress.

Here are four factors that can cause your weight to fluctuate from day to day.

Water Retention is Probably the Biggest Culprit

Anyone who has weighed in after a long run knows that weight can fluctuate day to day, or even hour to hour. But what caused these sudden changes?

One factor is water retention. When we sweat, our bodies lose not only water but also electrolytes like sodium and potassium. As a result, we may retain water in an attempt to replenish these lost minerals.

This can lead to a temporary increase in water weight.

Another factor that can impact water weight fluctuations is the food we eat. High-carbohydrate foods can cause our bodies to store glycogen, a form of sugar that is bound to water molecules.

So, if we eat a lot of carbs and then weigh ourselves shortly afterwards, we may see a spike in the number on the scale. However, this glycogen will eventually be used for energy or converted back into fat, leading to a gradual decrease in weight.

Metabolism Changes

Most people are familiar with the idea that metabolism affects weight. In general, a higher metabolism means that you will burn more calories and lose weight, while a lower metabolism means that you will store more calories and gain weight.

However, many people don’t realize that there are different types of metabolism, and that these can have a significant impact on weight fluctuation and calorie burn.

The two main types of metabolism are anabolic and catabolic.

Anabolic metabolism is responsible for storing energy in the body, while catabolic metabolism is responsible for releasing energy.

Anabolic metabolism usually occurs during periods of rest, while catabolic metabolism usually occurs during periods of activity.

As a result, your weight can fluctuate depending on how active you are and how much energy you are storing or releasing. Understanding this process can help you to better manage your weight.

Hormone Fluctuations

For women, hormone fluctuations throughout the monthly menstrual cycle affects how well your body is able to process sodium.

After ovulation, women’s bodies enter the luteal phase for the last 2 weeks of their cycle. This is when progesterone levels rise and estrogen drops. Your kidneys must work harder to process sodium at this time. The PMS-related bloating that occurs during the last 2 weeks of the menstrual cycle typically results in an increase of numbers on the scale, sometimes as much as 5 pounds, which actually has nothing to do with body fat.

If you’re a woman and you want to see less variance in your scale readout, especially during the last 2 weeks of your menstrual cycle when you’re prone to water retention, you can try to become more aware of how much sodium is in the foods you eat.

One easy way to reduce sodium is by avoiding processed foods. Even if billed as healthy, natural, low-fat, or low-carb, many packaged foods contain high amounts of sodium. This is designed to improve the taste so consumers will be more likely to enjoy, crave, and purchase these foods.

Bowel Movements

Anyone who has ever gone on a diet knows that the scale is not always a reliable indicator of progress. In addition to water weight, muscle mass, and how much you ate the night before, bowel movements can also affect your weight.

For example, if you are constipated, you may weigh more than usual because of the extra waste in your intestines. On the other hand, if you have loose stools, you may weigh less because you are losing water and electrolytes.

This is why it is important to pay attention to how your clothes fit and how you feel rather than fixating on the number on the scale.

By focusing on other measures of progress, you will be more likely to stick with your diet and achieve long-term success.


Although it can be frustrating to see your weight fluctuate, it is important to remember that these fluctuations are usually temporary and do not reflect any permanent changes in your body.

Weight fluctuating while you’re dieting is to be expected, especially when you are incorporating healthy eating and healthy habits into your life.

So, don’t freak out when you step on the scale and your weight is up. You know you’ve been doing all the right things, so just give your body a chance to catch up. And most of all, do not start beating yourself up with a lot of negative thoughts, self-talk, and a defeated attitude.

Scales are no more than a way to see where you’ve been and where you’re headed. Your weight will undoubtedly fluctuate, so it’s best not to wonder why. Just keep steady without weighing your self-worth on the bathroom scales.

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