How Should I Weigh Myself? Timing, Frequency and Reading the Trend

Weigh yourself at the same time, on the same scale and under the same conditions each time, ideally first thing in the morning after using the bathroom and before eating or drinking. Then judge your progress by your average over a week or more, not by any single reading.

Whether you weigh daily or weekly matters less than doing it consistently and knowing what the number can and can’t tell you. This guide covers what the research says about self-weighing, a simple routine, why the scale jumps around, how to work out a trend, and when frequent weighing isn’t a good idea.

The scale is one tool among several. Used well, it gives you useful feedback. Used badly, it can spoil your day over changes that have little to do with body fat.

What the research says about weighing yourself

Regular self-weighing is part of many weight-loss programs, and the trials behind it are fairly encouraging, with one important catch.

Weighing also seems to help people keep weight off. In an 18-month trial published in the New England Journal of Medicine, 314 adults who had already lost an average of about 42 pounds (19.3 kg) were assigned to a maintenance program that emphasized daily weighing, delivered face to face or online, or to quarterly newsletters.

Nearly three in four people in the newsletter group (72%) regained 5 pounds (2.3 kg) or more, compared with 46% in the face-to-face program and 55% in the online version. Daily weighing was linked with a lower risk of regaining that much.

Here’s the catch. A 2015 meta-analysis of randomized trials found only one study that tested self-weighing on its own, and it found no clear benefit. Self-weighing helped when it was added to a broader program that also changed eating and activity, and programs with some form of accountability did better.

In other words, the scale is a feedback tool. It works when you use what it tells you to adjust your habits, such as portions, snacks or daily steps. Our guide to how a calorie deficit works explains what you’re adjusting.

Daily or weekly: how often should you weigh yourself?

The same 2015 meta-analysis found no significant difference in weight loss between programs that asked people to weigh daily and those that asked them to weigh weekly. So the best frequency is the one you can keep up without it upsetting you.

If you weigh weekly, choose one day and keep it. As you’ll see below, weight often runs a little higher after the weekend, so comparing Monday with Monday is fairer than comparing a Monday with a Friday.

How to weigh yourself the same way every time

A routine removes as much noise as possible, so the differences between readings are more likely to reflect real change.

• Same time: first thing in the morning, after using the bathroom and before eating or drinking.
• Same clothing: nothing, or the same light clothes each time.
• Same scale, same spot: keep it on a hard, level floor rather than carpet, and leave it in one place.
• Same stance: stand still in the center with your weight evenly on both feet.
• Write it down: in an app, a spreadsheet or a notebook, so you can see the trend.

A basic digital bathroom scale is all you need. Some connected scales sync to an app and graph your readings automatically, which saves logging by hand, but extra features aren’t required to track your weight.

For other tools that can support a weight-loss routine, see our roundup of weight loss products.

Why your weight jumps around from day to day

The number on the scale includes water, stored carbohydrate and the food and drink still in your digestive system, as well as fat, muscle and bone. The first three can change noticeably from one day to the next, so a single high or low reading tells you very little.

Stored carbohydrate and water

Your body stores carbohydrate as glycogen, mainly in the liver and muscles, and glycogen is stored with roughly three to four parts water. When glycogen stores fill up or empty, the water goes with them.

That’s part of why weight can drop quickly in the first days of a strict diet, then bounce back when you eat more carbohydrate again. It’s water moving, not fat.

Weekends and holidays

Weight follows a weekly rhythm for many people. In data from more than 1,400 adults in a European weight-loss maintenance trial, weight rose over the weekend and fell during the week, a swing of about 0.35% on average. For a 180-pound person, that’s around 0.6 pounds.

The same study found weight rose by about 1.35% on average over the Christmas period and wasn’t fully lost again in the following months. That’s a good reason to keep an eye on your trend through the holidays, without panicking about any one day.

The menstrual cycle

If you have periods, you may notice bloating at certain points in your cycle. In a year-long diary study of 62 healthy women, self-reported fluid retention peaked on the first day of the period and was lowest partway through the first half of the cycle.

That study recorded how bloated women felt, not their weight. Still, if your readings creep up at the same point each month, comparing like with like, such as the same week of each cycle, gives you a fairer picture.

Read the trend, not the day

A trend average smooths out the noise. The simplest version is a 7-day average: add up your last seven readings and divide by seven, then compare one week’s average with the next.

Here is an example with made-up numbers for someone weighing daily.

Tuesday of week 2 was higher than most days in week 1, which could feel like a setback. But the weekly average dropped by about 0.6 pounds. That’s the signal; the daily ups and downs are noise.

• Use an app that shows a moving average, or keep a simple spreadsheet that calculates it for you.
• Judge your progress over two to four weeks, not two to four days.
• If your weekly average hasn’t moved after three or four weeks of consistent effort, review your eating and activity rather than reacting to a single number.

When frequent weighing isn’t a good idea

Daily weighing suits many adults who are trying to lose weight, but it isn’t right for everyone.

In a study of 758 people with eating disorders, those who weighed themselves more often tended to have more severe eating-disorder symptoms, especially among people with anorexia nervosa. The data were collected at one point in time, so they can’t show which came first.

Young women may be another group to be careful with. In a small 2-week trial, 69 university women aged 18 to 22 were randomly assigned to weigh themselves daily or take their temperature daily. The daily weighers had bigger negative mood swings, more weight-related stress and lower body satisfaction afterward.

That trial looked at weighing to prevent weight gain rather than as part of a weight-loss program, and it was short. But it’s a useful reminder that how the number makes you feel matters.

If you step away from the scale, you can still track progress through how your clothes fit, your waist measurement, your energy, your strength and your daily habits.

Common weighing mistakes

• Weighing several times a day. It adds noise, not information. Once a day is plenty.
• Reacting to one reading. Slashing calories after one high morning means reacting to noise. Wait for the weekly average.
• Changing the conditions. An evening reading after dinner isn’t comparable with a morning one.
• Comparing different scales. The gym scale and your home scale may not agree. Pick one and stick with it.
• Using the scale as your only measure. Waist size, fitness and how you feel all count. Our weight loss tips cover habits worth tracking too.
• Giving up after a flat week. One flat week can simply be noise. Look at a month of data before deciding your plan isn’t working.