How Much Weight Do You Actually Need to Lose?

Using a treadmill.
If you’re one of the one in three Australians whose New Year’s resolution involved losing weight, you’re likely contemplating what weight-loss goal you should be working toward. (Image: profivideos via Pixabay)

If you’re one of the one in three Australians whose New Year’s resolution involved losing weight, be working toward it.

But type “setting a weight loss goal” into any online search engine, and you’ll likely be left with more questions than answers.

Sure, the many weight loss apps and calculators available will make setting this goal seem easy. They’ll typically use a body mass index (BMI) calculator to confirm a “healthy” weight and provide a goal weight based on this range.

Your screen will fill with trim-looking influencers touting diets that will help you drop 10 kilos in a month, or ads for diets, pills, and exercise regimens promising to help you effortlessly and rapidly lose weight.

Most sales pitches will suggest you need to lose substantial amounts of weight to be healthy — making weight loss seem an impossible task. But the research shows you don’t need to lose much weight to achieve health benefits.

Using BMI to define your target weight is flawed

We’re a society fixated on numbers. So it’s no surprise we use measurements and equations to score our weight. The most popular is BMI, a measure of our body weight-to-height ratio.

BMI classifies bodies as underweight, normal (healthy) weight, overweight, or obese and can be a valuable tool for weight and health screening.

But it shouldn’t be used as the single measure of what it means to be healthy when we set our weight-loss goals. This is because it:

  • fails to consider two critical factors related to body weight and health — body fat percentage and distribution
  • does not account for significant differences in body composition based on gender, ethnicity, and age.
Losing weight can lower your blood pressure.
Losing weight can lower your blood pressure. (Image: tomwieden via Pixabay)

How does losing weight benefit your health?

Losing just 5-10 percent of your body weight — between 6 and 12k g for someone weighing 120 kg — can significantly improve your health in four key ways.

1. 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 your body produces and manages lipoproteins and triglycerides, another fat molecule you use for energy.

Having too much bad cholesterol and high triglyceride levels is not good, narrowing your arteries and limiting blood flow, which increases the risk of heart disease, heart attack, and stroke.

However, research shows improvements in total cholesterol, LDL cholesterol, and triglyceride levels are evident with just 5 percent weight loss.

2. Lowering blood pressure

Your 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 your sympathetic nervous system, blood vessels, and hormones regulate your blood pressure.

Essentially, high blood pressure makes your heart and blood vessels work harder and less efficiently, damaging your arteries over time and increasing your risk of heart disease, heart attack, and stroke.

Like the improvements in cholesterol, a 5 percent 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.

3. 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 your body regulates and uses the insulin your pancreas produces, leading to high blood sugar levels.

Type 2 diabetes can lead to severe medical conditions if it’s not carefully managed, including damaging your heart, blood vessels, major organs, eyes, and nervous system.

Research shows just 7 percent weight loss reduces the risk of developing type 2 diabetes by 58 percent.

4. Reducing joint pain and the risk of osteoarthritis

Carrying excess weight can cause your joints to become inflamed and damaged, making you more prone to osteoarthritis.

Observational studies show being overweight doubles your risk of developing osteoarthritis, while obesity increases the risk fourfold.

Small amounts of weight loss alleviate this stress on your joints. In one study, each kilogram of weight loss resulted in a fourfold decrease in the load exerted on the knee in each step taken during daily activities.

Losing weight eases stress on joints.
Losing weight eases stress on joints. (Image: Tumisu via Pixabay)

Focus on long-term habits

If you’ve ever tried to lose weight, but found the kilos return almost as quickly as they left, you’re not alone.

An analysis of 29 long-term weight-loss studies found participants regained more than half of the weight lost within two years. Within five years, they regained more than 80 percent.

When you lose weight, you take your body out of its comfort zone and trigger its survival response. It then counteracts weight loss, triggering several physiological responses to defend your body weight and “survive” starvation.

Just as the problem is evolutionary, the solution is evolutionary, too. Successfully losing weight long-term comes down to the following:

  • Losing weight in small manageable chunks, you can sustain, specifically periods of weight loss, followed by periods of weight maintenance, and so on, until you achieve your goal weight.
  • Make gradual changes to your lifestyle to ensure you form habits that last a lifetime.

Setting a goal to reach a healthy weight can feel daunting. But it doesn’t have to be a pre-defined weight according to a “healthy” BMI range. Losing 5-10 percent of your body weight will result in immediate health benefits.

At the Boden Group, Charles Perkins Centre, we are studying the science of obesity and running clinical trials for weight loss. You can register here to express your interest.

Nick Fuller, Charles Perkins Centre Research Program Leader, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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  • Troy Oakes

    Troy was born and raised in Australia and has always wanted to know why and how things work, which led him to his love for science. He is a professional photographer and enjoys taking pictures of Australia's beautiful landscapes. He is also a professional storm chaser where he currently lives in Hervey Bay, Australia.