some technical reasons :
1. Surface is sloppy. (Flat & hard surface is recommended)
2. 4 electrodes will work when the same amount of force is applied to it. if weight is not equally balanced on all electrodes then data won't be accurate.
3. do not shake your body while measuring.
Daily weight fluctuation is normal. The average adult’s weight fluctuates up to 5 or 6 pounds per day. It all comes down to what and when you eat, drink, exercise, and even sleep.
It’s usually the result of food or water intake
Your weight is determined by the number of calories you consume compared to the number of calories you burn.
Eating a healthy, balanced diet on par with the number of calories your body uses daily may reduce your chances of significant weight fluctuation over time.
But it can be a challenge to eat and drink in moderation every day. If your diet has been slipping, you may notice more weight fluctuation.
If you have a traditional Saturday and Sunday weekend, you may be able to get the most accurate measurement of your weekly weight by weighing yourself on Wednesdays.
Sodium and carbs cause water retention
Food high in salt and carbohydrates may cause your body to retain water. Your weight may spike until the bloat subsides.
You may be able to minimize water retention by cutting back on sugary drinks and processed foods.
Adding potassium– and magnesium-rich foods to your diet may also help balance out your sodium levels.
All food and drinks have some weight
No matter the caloric content, foods, and beverages all weigh something. Drinking an 8-ounce glass of water will add weight to your body because it has weight. The same is true for the vegetables in your salad.
However, healthy foods and water pass through your body quickly, so eating a balanced diet can mean less fluctuation. Foods high in carbohydrates, sodium, and fat take longer to process and expel through waste.
The resulting urine and stool also have weight
Your body uses foods and fluids for hydration and energy. After it’s successfully gleaned the nourishment it needs from these sources, it will begin to expel the leftovers as mucus, sweat, urine, and stool. This can cause a slight decrease in weight.
Exercise
Expending energy by burning calories can result in weight loss. But if you’re adequately hydrating, you may not see immediate weight loss on the scale. That’s because the water you drink replaces the water you’ve lost via sweat. Water, however, contains no calories and won’t cause weight gain over time.
Exercise burns calories, so if you burn more calories than you eat and drink, you will lose weight.
Medication
Some medications cause your body to retain water, increase your appetite, or change your metabolism.
If you think your medication is affecting your weight, make an appointment with the prescribing doctor.
They can help you determine the reason for fluctuation and discuss your options moving forward. This may mean switching medications or making dietary and fitness changes.
Menstrual cycle
Your menstrual cycle can cause your body to retain more water during certain times of the month, resulting in a slight weight gain. You may notice that your base weight is a bit higher than normal on the first day of your period. Your daily weight should go back to average within a few days of your cycle beginning.
Alcohol intake
Alcohol isn’t processed the same way as other beverages and foods, so it can take longer for your body to eliminate. It also slows the digestion of other substances, which can lead to water retention.
Beyond that, alcohol contains extra calories that you may not be accounted for in your overall diet.
Illness
Your weight may go up or down due to a bout of illness, like the flu, or as a result of a chronic condition.
While conditions like underactive thyroid, Cushing syndrome, and polycystic ovary syndrome can lead to unexpected weight gain, diabetes, and Crohn’s disease are often associated with unexpected weight loss.