Fasting, hydration, HIIT, cleanses. Add to that a cacophony of noise coming out of social media, diet brands, pharma pushing pill products and a bevy of workouts designed to trim and tone: when it comes to losing weight, there’s a wild amount of info out there. And with one in three Australians setting New Year’s resolutions around losing weight, it’s certainly as front of mind as ever.
When it comes to setting those goals, people have long turned to BMI to see the forest for the trees. But one expert is weighing in on it, saying that while calculating our BMI is useful in many ways, it isn’t the be-all and end-all when it comes to reaching a healthy weight. Additionally, while most people think that we should lose kilos upon kilos, actually we could benefit from losing far less than we often think.
What is BMI?
Body mass index, or BMI, is an equation that indicates your body size.
It’s calculated using your weight and height (your weight divided by your height squared). Along with several other factors, like your blood pressure and cholesterol, and it can help to determine your risk of a heart attack or stroke.
BMI classifies bodies as underweight, normal (healthy) weight, overweight or obese and can be a useful tool for weight and health screening.
Why we shouldn’t use BMI alone
Nick Fuller, Charles Perkins Centre Research Program Leader at University of Sydney argues that while it has its merits, BMI is not solely the best course.
“BMI fails to consider two critical factors related to body weight and health – body fat percentage and distribution. And secondly, it does not account for significant differences in body composition based on gender, ethnicity and age.”
The Heart Foundation corroborates this, stating that “It’s important to remember that BMI is not the most reliable measure of whether your weight is in a healthy range for your height. It’s not a good overall indicator of how healthy you are, and doesn’t take into account important factors like age, gender and body composition (fat, muscle and bone).
So how much weight should we aim to lose?
Instead of aiming for an astonishing – or unrealistic – amount, Fuller suggests that we only need to look at losing around 5 to 10% of our weight to significantly improve our health. And of course, this is only if we need to and we’re not in the healthy range.
Fuller outlines some key ways that losing just a little bit will help our long-term health:
Reducing cholesterol
Obesity increases the chances of having too much low-density lipoprotein (LDL) cholesterol – also known as bad cholesterol – because carrying excess weight changes how our bodies produce and manage lipoproteins and triglycerides, another fat molecule we use for energy.
Having too much bad cholesterol and high triglyceride levels is not good, narrowing our arteries and limiting blood flow, which increases the risk of heart disease, heart attack and stroke.
But research shows improvements in total cholesterol, LDL cholesterol and triglyceride levels are evident with just 5% weight loss.
Lowering blood pressure
Our blood pressure is considered high if it reads more than 140/90 on at least two occasions.
Excess weight is linked to high blood pressure in several ways, including changing how our sympathetic nervous system, blood vessels and hormones regulate our blood pressure.
Essentially, high blood pressure makes our heart and blood vessels work harder and less efficiently, damaging our arteries over time and increasing our risk of heart disease, heart attack and stroke.
Like the improvements in cholesterol, a 5% weight loss improves both systolic blood pressure (the first number in the reading) and diastolic blood pressure (the second number).
A meta-analysis of 25 trials on the influence of weight reduction on blood pressure also found every kilo of weight loss improved blood pressure by one point.
Reducing risk for type 2 diabetes
Excess body weight is the primary manageable risk factor for type 2 diabetes, particularly for people carrying a lot of visceral fat around the abdomen (belly fat).
Carrying this excess weight can cause fat cells to release pro-inflammatory chemicals that disrupt how our bodies regulate and use the insulin produced by our pancreas, leading to high blood sugar levels.
Research shows just 7% weight loss reduces risk of developing type 2 diabetes by 58%.
Reducing joint pain and the risk of osteoarthritis
Carrying excess weight can cause our joints to become inflamed and damaged, making us more prone to osteoarthritis.
Observational studies show being overweight doubles a person’s risk of developing osteoarthritis, while obesity increases the risk fourfold.
So, what’s the good news?
If the above tells us anything it should be that a little bit of weight loss goes a long way. And that this goal is an achievable, positive one that can be much more easily sustained.
In fact, if you needed any more persuading as to why achievable goals are best, a study involving participants of a long-term weight-loss regime, which included dramatic rapid weight loss, concluded with most regaining more than half of their weight lost within two years. Within five years, they regained more than 80%. This demonstrated that more drastic dieting is difficult to sustain and exemplified the benefits of aiming small.
So, there you have it; make tweaks and gradual changes to your lifestyle, and you’ll see much better long-term benefits. Hurrah!
