How To Measure And Track Your Weight Loss

It is a little demotivating when you stick to your diet and exercise regimen and still seem unable to lose weight. Before giving up, know that you shouldn’t place too much weight on the numbers on your scale. Learn how to take body measurements for weight loss so you can track your progress accurately.

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Why your scale doesn’t tell the whole story

A standard scale measures one thing: your body weight. It’s unable to differentiate between weight due to water retention, the huge meal you’ve just eaten, or muscle that you may have gained due to your training plan.

The following factors can influence the reading on your scale.

Your body’s water weight

When we are young, our bodies are made up of about 75% water¹. As we get older, this percentage gradually declines until we reach around 55% water when we are elderly.

If the percentage of water in our bodies increases above the normal average and what our bodies can utilize, fluid retention happens. Consequently, our water weight and overall weight increase.

Some of the common causes of excess water weight are hormonal changes² (such as premenstrual syndrome, using contraceptive pills, or pregnancy in females), high salt intake³, and high carbohydrate intake⁴. Just having a salty dinner can push your weight up the following morning.

Your body composition (how much fat and how much muscle you have)

Muscle is denser than fat, so a pound of muscle looks very different from a pound of fat. Once you are well on your way with your diet and exercise program, you should be losing fat and gaining muscle.

When you step on your bathroom scale, it is unable to tell the difference between the fat that you’ve lost and the muscle you’ve gained. So although the weight on your scale may not have dropped as much as you might have hoped, you may look very different from the way you did before you started your weight loss journey. 

Your weight fluctuates

Your weight changes throughout the day according to what you are wearing, what you eat, what you drink, how much you’ve sweated, and how much you’ve exercised. If you don’t weigh yourself at precisely the same time each day, the reading you get on your scale won’t accurately reflect your change in weight.

A bathroom scale can be useful, but to track your weight as accurately as possible, you need to weigh yourself at the same time—ideally, first thing in the morning before you’ve eaten or drunk anything—and under the same conditions each day.

Your body mass index (BMI)

You may have heard of body mass index (BMI), as it’s often used to define underweight, overweight, and obesity. There is a flaw with using the BMI, though.

BMI is calculated by dividing your weight (kg) by your height squared (cm)⁵. If you are very muscular, your BMI will be on the higher side. The BMI reading will define you as overweight, even though your body fat percentage could be very low.

You can’t read too much into your BMI measurement, then, if you are more muscular than average.

How to measure weight loss accurately

The fundamental issue with measuring weight loss with a scale or BMI is that neither of them take into account body composition. The following ways of measuring weight loss are more accurate because they are able to differentiate between fat and muscle loss or gain.

1. Skin calipers

Skin calipers are a simple tool that measures the amount of fat that you have just under your skin (skinfold or subcutaneous fat). Measurements are taken at different places on your body and then entered into a formula that gives your body fat percentage and lean muscle mass percentage.

Regular skinfold measurements are a great way to monitor fat loss and lean muscle gain, provided the measurements are taken by someone who is experienced and trained in using skin calipers.

2. Impedance scales

Impedance scales, or body fat scales, use bioelectrical impedance to measure your body fat.

You stand on the scale barefoot, and a weak electrical current is transmitted through your body. The scale measures the resistance to the current, which varies depending on your body composition.

Bioimpedance scales are a simple way to measure body fat, but they can be inaccurate depending on hydration changes and the quality of the scale⁶. These scales can range from cheap supermarket options, which usually only measure the composition of your legs (then extrapolate that reading to the rest of your body), to expensive, more accurate models that have hand bars and send a current through your whole body.

3. DEXA (dual energy x-ray absorptiometry) scanning

DEXA scanning is considered the gold standard in measuring body composition for weight loss management. It uses an X-ray beam passed over your body to measure body composition.

DEXA scanning can precisely measure body fat percentage changes as well as lean muscle mass changes⁷. It is relatively widely available, as it is used in most major research and high-performance sports centers.

Hydrodensitometry, air displacement plethysmography, hydrometry, computed tomography, and magnetic resonance imaging (MRI) are other highly accurate ways of measuring body composition. However, they are not easily accessible, and some may have radiation risks and are costly⁷.

4. Body measurements

Taking body measurements is a simple way to monitor whether you are losing fat and gaining muscle. Remember that muscle is denser than fat. This means that one pound of muscle will take up less space than one pound of fat.

You can visualize this by measuring the circumference of different areas of your body. All you need is a tape measure.

Ideally, measure yourself naked or wearing tight-fitting clothes, in the following areas:

  • Bust: Around your chest at the nipple line 

  • Calves: Around the largest part of each calf 

  • Chest: Just under your bust 

  • Forearm: Around the largest part of the forearm (under the elbow)

  • Hips: Around the widest part of your hips 

  • Thighs: Around the largest part of each thigh

  • Upper arm: Around the biggest part of each arm (above the elbow) 

  • Waist: Around the smallest part of your waist, or slightly above your belly button 

Although body measurements don’t give you your body fat percentage, they are a simple, cheap, and easy way to monitor your body changes.

How often should you measure your weight?

The jury is still out on this one. At the end of the day, you just have to find what works for you.

One large study of 1,042 participants found that those who weighed themselves once per week or less didn’t lose weight. In contrast, those who weighed themselves six or seven times per week lost an average of 1.7%⁸.

Daily weigh-ins may work for some people, but for others, it may be a demotivating exercise because weight loss is a slow process and weight can fluctuate on a daily basis.

For example, a review of 20 published studies concluded that repetitive self-weighing can have a negative impact on mood, anxiety, self-esteem, and eating behaviors, particularly in women and young adults. However, it had a neutral or positive impact on people who were overweight and pursuing treatment⁹.

If you choose to monitor your progress using skin calipers or another method of body fat measurement, you may want to stretch your measurements out to every two weeks, as body fat percentage takes a longer time to change noticeably.

Whatever method you choose, it’s important that you take your measurements under the same condition each time and that you keep a record of your readings so that you can track your progress.

Most importantly, try not to obsess over the numbers and the measurements. Ultimately, what matters is the changes that you can see in your body from health, physical appearance, or fitness perspective, and how you feel about yourself.

The lowdown

Losing weight is more complex than just watching the numbers move on a scale. It’s more accurate to monitor your progress by measuring changes in your body composition.

Know what to measure for weight loss so you don’t get off track. Your goal should be to decrease your percentage of body fat while maintaining or increasing your lean muscle mass. Ways to measure body composition range from body measurements and skin caliper measurements, to bioelectrical impedance scales and DEXA scanning.

Some people find that weighing in daily helps keep them accountable, while others find it more productive to measure their weight loss biweekly or even monthly.

Just keep in mind that to succeed in your weight loss journey, you should choose the method that works best for you, and keep a record of your progress. Consistency is key.

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