How Often Should We Weigh Ourselves?

Weighing yourself daily can lead to obsession and unhealthy behaviors, such as following unsustainable fad diets.

Few topics are as hotly debated in the health field as the value of the humble bathroom scale.

Some experts recommend weighing yourself daily to monitor your weight, especially when following a diet and exercise program to lose weight.

And many, including myself, recommend weighing yourself weekly, even when you’re not trying to lose weight. Here’s why.

Weighing yourself weekly helps you control your weight

Recent research confirms that regular weighing is an effective strategy for losing and controlling weight, mainly because it helps to increase awareness of our current weight and detect changes.

A systematic review of a dozen studies found that participants who weighed themselves weekly or daily for several months lost 1 to 3 BMI (body mass index) units more and regained less weight than participants who did not step on the scale frequently.

Self-weighing is an essential tool for weight management as we age. Adults tend to gain weight progressively throughout middle age. Although the average weight gain is usually between 0.5 and 1 kg per year, this modest weight gain can lead to obesity over time. Weighing yourself weekly and keeping track of the results helps prevent unnecessary weight gain.

Keeping track of our weight can also help us identify medical problems early. Drastic weight changes can be an early sign of some conditions, such as thyroid problems, digestion, and diabetes.

Weekly weighing takes into account normal fluctuations

Our body weight can fluctuate within a day and across the days of the week. Several studies indicate that body weight fluctuates by 0.35% during the week and is usually higher after the weekend.

Daily and everyday fluctuations in body weight have several explanations, many of them related to the water content of our body. The most common causes include:

1. The type of food we have consumed.

If we eat a meal rich in carbohydrates, we will weigh more the next day. This change is the result of our body temporarily carrying more water: we retain about 3-4 grams of water for each gram of carbohydrate consumed to store the energy they provide us.

Our water content also increases when we consume foods richer in salt. Our body tries to maintain a balance of sodium and water. So when the concentration of salt in our bloodstream increases, a mechanism is put in place to restore the balance, by retaining water to dilute the excess salt.

2. Our food intake

Whether it’s 30 grams of nuts or 65 grams of lean meat, everything we eat and drink has weight, temporarily increasing our body weight while we digest and metabolize what we’ve consumed.

Our weight also tends to be lower first thing in the morning, after having restricted our food intake during the night. And higher in the afternoon, after our daily intake of food and drink.

3. Exercise

If you step on the scale at the gym after a workout, you’re likely to weigh less due to sweat-induced fluid loss. The amount of water lost varies depending on factors such as exercise intensity and duration, temperature and humidity, as well as sweat rate and hydration level. On average, we lose 1 liter of sweat during an hour of moderate-intensity exercise.

4. Hormonal changes

Hormonal fluctuations during the menstrual cycle can also affect fluid balance. Women may experience fluid retention and temporarily gain 0.5-2 kg in weight during this period. Specifically, the luteal phase, which represents the second half of a woman’s cycle, causes a shift of fluid from blood plasma to cells and swelling .

5. Bowel movements

Going to the bathroom can cause a small but immediate weight loss as waste is removed from the body. Although the amount lost varies, we generally eliminate around 100 grams of weight through our daily bowel movements.

All of these fluctuations are normal, and they are not indicative of significant changes in our body fat or muscle mass. However, seeing these fluctuations can cause us to obsess about our weight and create unnecessary stress.

Weighing yourself weekly prevents you from becoming obsessed with the scale.

Weighing yourself too often can create an obsession with the number on the scale and do us more harm than good.

Often, our reaction when we see that the number isn’t moving in the direction we want is to restrict our food intake even further or jump on the latest fad diet. Besides not being enjoyable or sustainable, fad diets end up making us gain even more weight.

This was confirmed by a long-term study comparing intentional weight loss among more than 4,000 twins. Researchers found that the likelihood of being overweight at age 25 was significantly higher in twins who dieted to lose 5kg or more. This suggests that frequent dieting makes us more susceptible to weight gain and more likely to become fatter in the future.

What should be done?

Weighing yourself weekly provides a more accurate measure of your weight trends over time. Ideally, you should weigh yourself on the same day of the week, at the same time, and in the same environment each week. For example, every Friday first thing in the morning before you get in the shower or after you’ve used the bathroom, but always before you’ve had anything to eat or drink.

It is advisable to use the best quality scales you can afford. It is also a good idea to change the batteries regularly and check their accuracy using a “known” weight, for example, a 10kg plate, to confirm that it matches the weight indicated.

Remember that the number on the scale is only one part of managing your health and weight. Focusing solely on it can overshadow other indicators, such as how your clothes fit. And it’s also essential to pay equal attention to how you feel, physically and emotionally.