Is weight a good measure of fitness?

When you think about fitness, weight is often the first thing that comes to mind. However, relying solely on weight as a measure of fitness doesn't provide a complete picture of your health.

In this video, Dr Bryony, a weight loss expert and Numan’s Medical Director, explains why weight isn't necessarily the best measure of your fitness level:

Understanding what truly defines fitness is crucial. A recent study suggests that fitness, rather than just weight, is a more accurate indicator of health. 

What the study says

Before we dive into the study details, let's clarify the difference between weight and fitness. Weight is a numeric measure of how heavy you are, typically assessed using scales and often discussed in terms of Body Mass Index (BMI). Fitness, on the other hand, is a broader measure of physical health and capabilities, including strength, endurance, flexibility, and cardiovascular health.

Researchers explored whether being fit is more beneficial for your health compared to just managing your weight. As obesity levels rise, it poses an important question: should we focus more on boosting fitness or just losing weight?

Traditional health advice often emphasises weight loss, but many people regain lost weight, and shedding pounds doesn't always mean you'll live longer. In contrast, being fit is consistently linked with less heart disease and longer life.¹

The study analysed data from 20 research papers involving nearly 400,000 people to get to the bottom of this issue.¹

Here's a summary of the findings:

1. Overweight or obese people who are fit have the same risk of dying as fit people of normal weight.¹

2. Unfit individuals, even if they’re a normal weight, face double the risk of dying from any cause compared to fit people.¹

3. Fit individuals, regardless of being overweight or obese, don’t have a higher risk of heart problems compared with fit, normal-weight individuals.¹

4. Unfit individuals are 2-3 times more at risk of heart issues.¹

How to check your fitness and health

You don't just have to rely on a scale to see how healthy you are. Here are some other measures of health:

• Body fat percentage: Use skinfold calipers or body fat scales to measure body fat. 

  • Men: 25% body fat is considered "overweight," and 30% is considered "obesity".

  • Women: 36% body fat is considered "overweight," and 42% is considered "obesity".²

• Waist circumference: Abdominal fat is linked to heart issues. Measure your waist midway between your ribs and hips.

  • Men: A waist circumference of 102 cm or more is considered a higher risk for health complications.

  • Women: A waist circumference of 88 cm or more indicates an increased health risk.³

• Blood pressure: Keeping an eye on your blood pressure is key. Use a reliable monitor and follow simple steps for accuracy: sit down, relax, and put the cuff on your upper arm. Regular checks help catch any issues early.⁴

• Cholesterol levels: Focus on LDL levels, as they correlate with heart risk. Regular check-ups can help keep track of your levels so you can take proactive steps to prevent heart disease and protect your cardiovascular health.⁵

• HBA1c test: Screen for diabetes using this blood test, which measures your average blood sugar level. A normal reading is below 5.7, while 5.7 to 6.4 indicates prediabetes.⁶

• VO₂ max: This is a measure of how well your body uses oxygen during exercise. Think of it as your fitness ceiling - the higher it is, the more efficiently your heart, lungs, and muscles work together.⁷

• Resting heart rate: Your resting heart rate is an indicator of your overall fitness level.⁸ Regular cardiovascular exercise can lower your resting heart rate over time, which implies a more efficient heart function.

For a comprehensive overview of your health, a Numan Full Check-Up gives you in-depth insights into potential risks for heart disease, kidney issues, diabetes, and high cholesterol. These secure and accurate tests offer actionable insights so you can make informed decisions about your health.

The numan take

Forget the scale. Real fitness is about moving and keeping your heart and muscles strong. Mix up your workouts and eat well to not only live longer but live better too. 

References

1. Weeldreyer, N. R., et al. (2024). Cardiorespiratory fitness, body mass index, and mortality. British Journal of Sports Medicine, 59(5).

2. Potter, A. W., et al. (2024). Defining overweight and obesity by percent body fat instead of body mass index. The Journal of Clinical Endocrinology and Metabolism, 110(4).

3. Ross, R., Neeland, I. J., Yamashita, S., Shai, I., Seidell, J., Magni, P., Santos, R. D., Arsenault, B., Cuevas, A., Hu, F. B., Griffin, B. A., Zambon, A., Barter, P., Fruchart, J. C., Eckel, R. H., Matsuzawa, Y., & Després, J. P. (2020). Waist circumference as a vital sign in clinical practice: a Consensus Statement from the IAS and ICCR Working Group on Visceral Obesity. Nature reviews. Endocrinology, 16(3), 177–189. https://doi.org/10.1038/s41574-019-0310-7 

4. Muntner, P., Einhorn, P. T., Cushman, W. C., Whelton, P. K., Bello, N. A., Drawz, P. E., Green, B. B., Jones, D. W., Juraschek, S. P., Margolis, K. L., Miller, E. R., 3rd, Navar, A. M., Ostchega, Y., Rakotz, M. K., Rosner, B., Schwartz, J. E., Shimbo, D., Stergiou, G. S., Townsend, R. R., Williamson, J. D., … 2017 National Heart, Lung, and Blood Institute Working Group (2019). Blood Pressure Assessment in Adults in Clinical Practice and Clinic-Based Research: JACC Scientific Expert Panel. Journal of the American College of Cardiology, 73(3), 317–335. https://doi.org/10.1016/j.jacc.2018.10.069

5. Sundjaja JH, Pandey S. Cholesterol Screening. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560894/ 

6. Sherwani, S. I., Khan, H. A., Ekhzaimy, A., Masood, A., & Sakharkar, M. K. (2016). Significance of HbA1c Test in Diagnosis and Prognosis of Diabetic Patients. Biomarker insights, 11, 95–104. https://doi.org/10.4137/BMI.S38440 

7. Strasser B. Survival of the fittest VO sub 2 sub max a key predictor of longevity. Front Biosci [Internet]. 2018;23(8):1505–16. Available from: http://dx.doi.org/10.2741/4657 

8. Gonzales, T. I., Jeon, J. Y., Lindsay, T., Westgate, K., Perez-Pozuelo, I., Hollidge, S., Wijndaele, K., Rennie, K., Forouhi, N., Griffin, S., Wareham, N., & Brage, S. (2023). Resting heart rate is a population-level biomarker of cardiorespiratory fitness: The Fenland Study. PloS one, 18(5), e0285272. https://doi.org/10.1371/journal.pone.0285272