Search
  • Elaine Zhang, Dietitian

Do you have a healthy weight?

Is your weight healthy? Do you need to lose weight? Does your weight put you at higher risk of diseases or chronic diseases? Today, we will explore 3 important measures for healthy weight. If you only rely on the numbers on the weight scale, you may have overlooked more important information about your weight.

Overview for today's article: 1. What is body mass index? How to calculate body mass index (BMI)? What does body mass index mean? Are there any disadvantages of using body mass index? 2. How to measure my body fat percentage? What is a healthy range of body fat percentage? Is it accurate to use a weight scale to measure my body fat percentage? 3. What is a healthy range of waist circumference? How to reduce the risk of chronic diseases?



Body mass index (BMI) Body mass index (BMI) is a good measurement that we use to predict some risk factors. Being overweight or obese can increase our risks of chronic diseases such as cardiovascular diseases, some cancers, diabetes, fatty liver, sleep apnea and etc. BMI too low may also have some negative health consequences. It may increase risks of malnutrition, poor immunity, infertility, irregular menstruation or even amenorrhea. Therefore, it is not recommended that you lose weight blindly in pursuit of a small waist. Before deciding to lose weight or not, I would suggest you to calculate your BMI.

How is BMI calculated? We use height and weight. Weight is measured in kilograms and height is measured in meter. Body mass index = weight (kg) / height (m) * height (m) For example, for a person with a height of 160cm and a weight of 52 kg, BMI = 52kg/1.6 x.6 = 20.3

What is the range of body mass index? Underweight (BMI <18.5) Normal weight (BMI18.5-24.9) Overweight (BMIs 25-29.9) Obesity (BMI> 30)


What are some limitations for BMI? First, BMI does not consider the ratio of muscle to fat. For some people who are very muscular, BMI is not a good measurement. Secondly, we don't use BMI for pregnant women. We use pre-pregnancy weight to calculate BMI, but as they gaining weight during pregnancy, BMI is not an accurate measure to use during pregnancy. Thirdly, infants and children under 19 may have a different standard. Lastly, for the elderly over 65 years old, they may also have different standards for BMI. You can consult a doctor or registered dietitian to learn more about it.


Body fat

More and more people realize that weight only provides us with limited information, and BMI does not consider the ratio of muscle to fat. Body fat percentage has become an popular indicator that many people care about. Body fat is reflection about how much fat in our body.


How do I know my body fat percentage?

There are a few ways to measure. In some clinics, a skin-fold test is done using calipers to pinch different areas of your body to estimate body fat. More accurate methods include dual-energy X-ray absorption measurement (DXA) or underwater weighing measurement. However, these methods are not realistic for many people to do.


The most common way that many people use is to measure body fat at home using a weight scale. The current technology mainly uses bioelectrical impedance analysis (BIA). However, the weight scale is not a very sensitive or accurate method. There are some external factors that may cause errors such as dehydration, moderate to high-intensity exercise, eating and drinking etc.


How to use the weight scale and know your body fat percentage more accurately?

I have 2 suggestions:

First, track over a period of time. Try not not use a single number to determine whether your body fat percentage is too high or not. We can track changes in body fat overtime. Looking at the overall trend is more reliable.


Second, try to be more consistent in terms of when you measure your body fat, such as weighing yourself when you get up in the morning on an empty stomach; avoiding to measure your body fat after high-intensity exercise or after eating and drinking.


What is a healthy range for body fat?

The recommendation for a healthy body fat percentage is not completely may vary depending on ethnicity, age, gender or whether you are an athlete.


According to the ACE fitness, adult men with a body fat more than 25% and women with a body fat more than 32% are considered as obesity. Too much and too less body fat may be linked to health risks.


Are there any limitations of using body fat percentage?

Body fat percentage alone does not indicate where body fat accumulates. The location of fat is closely related to our health risks.


Waist circumference

This brings us to the last measurement that we are going to talk about today - waist circumference.


Many people have heard of apple-shaped and pear-shaped body. Apple-shaped body means that more fat is accumulated around the waist area. Fat accumulation in the abdomen is more dangerous, because most of our internal organs are there. It is more correlated with chronic diseases risks such as fatty liver, cardiovascular disease, heart diseases, and type 2 diabetes. The pear-shaped body has fat accumulated in the butt area, mostly subcutaneous fat, which is relatively safer.


What is a healthy range for waist circumference? Generally speaking, men's waist circumference of more than 90 cm will increase the risk; women's waist circumference of more than 80 cm will increase our health risks.

In summary, I think that combining waist circumference and BMI are a very meaningful in deciding whether a person has higher health risk factors. Waist circumference and BMI are complementary to each other. One of the limitations of BMI is that it cannot reflect the distribution of fat. If you know the waist circumference, you can better understand where fat is accumulated.


If your BMI is in a healthy range but the waist circumference exceeds the safe range, the chronic disease risks will still increase. If the BMI and waist circumference both exceed a healthy range, the risks are much more increased. If you have any nutrition questions or want to lose weight or gain weight, you can contact a dietitian for tips and healthy meal ideas.



References:

1. ACE. https://www.acefitness.org/education-and-resources/lifestyle/tools-calculators/percent-body-fat-calculator/

2. 6 Ways to Measure Body Fat Percentage. https://www.healthline.com/health/how-to-measure-body-fat

Recent Posts

See All