We’re a society obsessed with weight. Almost every bathroom has a scale in it and in the US alone, the weight loss industry is worth over $66 billion per year. Many weight loss programs promote health as a reason to lose weight, and I’m sure a lot of us have been weighed at the doctor’s office. It would stand to reason then that our weight is a measure of our health. Wrong.
A person’s weight does not tell you how healthy that person is. It never has, and never will. So what does our weight tell us?
While it’s true that our weight can be affected by our health, it doesn’t mean that we can tell if someone is healthy or not by their weight. When we weigh ourselves we may be interested in how much fat we have as body fat is associated with an increased risk for diseases such as diabetes, heart disease and some cancers. But weight is more than just fat, it includes our lean tissue (mostly muscle) and bone as well.
In the doctor’s office or in some weight loss programs, weight is converted into the body mass index (BMI) measure, which is a function of weight over height. And from there, we have BMI categories of underweight, normal, overweight and obese. People whose BMI falls within the overweight and obese categories may be at increased risk for disease, likewise with being underweight.
But a single weight measure, and BMI by extension, is pretty useless. Whether I’m 170 pounds or 185 pounds doesn’t tell me if I’m healthy or not. Sure, if you take 1000 people and calculate their BMI, those people with higher weight and BMI values generally have the greater amount of fat. This is helpful to know when we’re dealing with populations, but when it comes to individuals, it’s not so great.
While a higher amount of body fat is not good, a higher amount of muscle is, and your weigh scale can’t tell you which is which. Take Dwayne Johnson. He weighs 260 pounds. Much more than most people on this planet. With a height of 6’ 4”, his BMI is nearly 32 kg/m2. This makes him clinically obese. So is he unhealthy? He certainly doesn’t look it, and I don’t think we need to take his weight to come to come to that conclusion.
There are also plenty of people who are of ideal or normal BMI who are not healthy, and people who may be considered overweight, or even obese, who are in better physical shape, and may have lower risk factors than people who are thinner. One study found nearly 1/3 of overweight people to be healthy based on their risk factors (blood pressure, blood sugar and cholesterol), while a third of normal weight people had worse risk factors. Now risk factors only capture one aspect of health and people with excess fat may also be at risk for joint pain, but this example highlights the problems with looking at weight and BMI alone.
When it comes to body fat, it’s just like real estate; location, location, location. Body fat around the waist is associated with greater risk for disease than fat elsewhere. It is the apple shape (bigger waist) versus the pear shape (bigger hips) discussion. This is because of the type of fat and fat cells that sits around our waist is different. It is more metabolically active and causing more trouble. That person who may have a normal BMI could still have an elevated waist and be at greater risk for disease than someone who is overweight may have excess body fat around their hips and a slim waist. While a lot of people may not desire fat around the hips, it isn’t as problematic with respect to health risks.
So if weight can’t tell us how much fat we have and where it is, then why do doctors weigh their patients?
For many people it’s to calculate BMI and compare that to the BMI categories to get a sense of a person’s risk for disease. Even though there are many problems with BMI, it’s still used because it’s easier than any other measure of body fat. At the same time, your doctor may also be measuring your blood pressure and send you for a blood test to get a sense of your blood sugar and cholesterol levels. Once your doctor has those measures, however, knowing one’s weight doesn’t really add anything to informing how a patient is treated.
Another reason for weighing is to get a starting, or baseline, measure for future weight/BMI measures. While weight measures more than just fat, for most adults, a change in weight is usually due to a change in fat. In that case, it may help get a sense as to whether someone’s health risk is going up or down, but again, it won’t tell you where the fat is put on or taken off. And it won’t tell you if you’re healthy or not.
For some people with heart or kidney failure, weighing daily is part of good self-care. This is because an increase in weight may be the result of fluid (water) retention, which may reflect that the heart or kidney is getting weaker. And it is common for people who have a severe illness for their weight to change dramatically, but in these cases it is pretty obvious to the person and those around them that their weight is changing without actually having to weigh a person.
Should I stop weighing myself?
Full disclosure; I weigh myself every few weeks. A few years ago I also measured my waist circumference, or rather had my wife do it, but that became too much of a hassle and it was tough measuring it myself. Yes, my weight does fluctuate. I use this as a reflection of how my diet and exercise is doing. But I don’t use weight in isolation. I look at how my food intake has been doing (for example, have I had much alcohol recently) and how much activity I’ve been getting. But really, I can tell whether I’ve gained or lost weight before getting on my scale by how my clothes fit and how my lifestyle has been the past couple of weeks.
It would be hypocritical of me to say not to weigh yourself. If you are going to do so, put your weight into context, knowing what it is good for and what it isn’t. There are studies that show people who weigh themselves regularly are more successful at weight loss. In these cases it likely provides that accountability and feedback on one’s lifestyle as I find with myself. However, one shouldn’t obsess over their weight nor mistake their body weight for defining how healthy they are. Taking stock of your lifestyle (nutrition, activity, sleep patterns, etc.) will do more to tell you about your health than weight or BMI.