The bottom line It's totally normal for our weight to go up and down. This can happen because of the food we eat, how much water our body holds or even how active we are.
Why Does My Weight Fluctuate So Much? Since many people can't eat enough in a day or two to actually gain 5 or 10 pounds, if you notice a dramatic increase on the scale, chances are it's due to water, says Anita Petruzzelli, M.D., owner and medical director of BodyLogicMD.
Your body (everyone's bodies) generally can fluctuate up to 5-10 pounds in a single day just based on eating, urination, bowel movements, water retention, etc. In addition, people who do IF often have particularly wide swings as all of your eating happens in a specific period of time.
The reality is, small changes in weight are completely normal and expected. Body weight can shift throughout the week and even during the day. In fact, an average adult can lose or gain two to eight pounds over the course of a few days.
Your weight can fluctuate daily due to a variety of factors such as water retention, food consumption, exercise, hormonal changes, and bowel movements. These fluctuations are normal and can be influenced by many different variables.
The bottom line
It's totally normal for our weight to go up and down. This can happen because of the food we eat, how much water our body holds or even how active we are.
So even though you may be losing fat, you're gaining muscle. You might feel slimmer, even as the number on the scale rises. “The scale doesn't tell the entire story,” said exercise physiologist Christopher Mohr, PhD, RD. “Since muscle and fat take up different volume, they look very different on the body.”
Water retention may clear without treatment in a few days. However, if there is a health problem causing you to hold onto fluid, your swelling may worsen over time. You may find that the body parts retaining water become tight, swollen, and painful. If untreated, heart or kidney problems may get much worse.
Aim to weigh yourself on the same day, at the same time and in the same environment each week – for example, first thing every Friday morning when you're getting ready to take a shower, after you've gone to the bathroom, but before you've drunk or eaten anything.
Fluid retention
The amount of fluid in your body changes throughout the day. It's totally normal for your weight to change up to four pounds in a single day, based on your fluid levels. Fluid retention, or edema, is when a lot of fluid builds up in the body. This can cause a sudden weight gain of 15 or more pounds.
The “whoosh effect” is a term for the noticeable weight loss that some people report while following low carb diets such as a keto diet. Some people believe that the whoosh effect happens when fat cells lose fat and fill with water. Researchers have not scientifically proven the whoosh effect, however.
“Your skin is the largest organ in the body and absorbs fluid easily,” says Dr. Keith Kantor, a leading nutritionist and CEO of the Nutritional Addiction Mitigation Eating and Drinking (NAMED) program. “After a swim or a shower, your body can absorb 1 to 3 cups of water, increasing your true weight by a few pounds.”
Water retention, hormones, medications, what you eat, and how active you are can all contribute to weight fluctuation. You might notice these changes throughout the day or during certain times, such as menstruation or on weekends or holidays.
Drinking Too Much Water
A quart of it weighs about 2 pounds. If you just drink it -- and you don't exercise -- that'll show up on the scale right away. That doesn't mean you should give up H2O. In the long run, drinking water (especially instead of high-calorie sugary beverages) can help you lose weight.
Weight gain and short-term fluctuations may happen for a variety of reasons, such as aging or making lifestyle and dietary changes. However, fast weight gain can be a sign of an underlying health condition, such as a problem with the thyroid, kidneys, or heart.
Muscle weighs more than body fat
This means that muscle and fat may look the same on the scale, but they'll look different on your body. While your clothes may feel looser, the scale may tell you otherwise. Count this as a win.
The rule of thumb, Fernstrom says, is that losing 8 to 10 pounds translates to going down one size. Still, if you lose "up to 15 pounds, you may be OK in your old size," she says. But putting off buying new clothes until you really need them doesn't work for everyone.
Daily weighing is emerging as the recommended self-weighing frequency for weight loss. This is likely because it improves adoption of weight control behaviors.
"We can weigh 5, 6, 7 pounds more at night than we do first thing in the morning," Hunnes says. Part of that is thanks to all the salt we consume throughout the day; the other part is that we may not have fully digested (and excreted) everything we at and drank that day yet.
Many women notice an increase in belly fat as they get older even if they don't gain weight. This is likely due to a lower level of estrogen because estrogen seems to have an effect on where fat is located in the body. Genes can contribute to an individual's chances of being overweight or obese too.