Longevity can be influenced by many health conditions and different lifestyles, and obesity is definitely one of them. As a chronic condition defined as having the body mass index higher than 30, obesity can significantly reduce your average life expectancy. Being obese can cause the development of many other health conditions, and in combination, all of them will cause you to have a shorter life expectancy.
In this article, we will explore the ways in which obesity impacts longevity, and discuss average life expectancies of different categories of obesity. Keep reading and find out more!
How is obesity defined?
Obesity is defined as an abnormal or excessive fat accumulation, that poses a great risk to your health. The World Obesity Atlas predicts that more than half of the world population will either be overweight or obese in the next twelve years if current trends continue (1).
Obesity is considered to be a chronic disease that results in the development of other diseases (comorbidities) (2), such as:
- cardiovascular diseases,
- diabetes type II,
- hormonal imbalances,
- metabolic syndrome,
- chronic inflammation.
- increased risk of cancer.
Obesity also impact your life quality, and it can cause reduced function and mobility, as well as negatively impact mental health. Obesity is often linked with depression and anxiety, as well as social stigma, which can cause more health problems as well.
There isn't one sure way to determine obesity, even though the most used method is to calculate your BMI or your body mass index. You can calculate it by dividing your body mass in kilograms by the square of your height in meters. The BMI of a person with normal weight is 18.5-24.9 and of an obese person > 30 (3).
The BMI is not always a surefire way to determine obesity. Other ways to determine if someone is obese are to measure:
- Waist Circumference - it measures the amount of fat stored around your abdomen. For women, the healthy threshold is under 88 cm, and for men under 102 cm.
- Body Fat Percentage - measuring the fat percentage of your body is a more accurate way to determine if you're overweight or obese. This can be measured by bioelectrical impedance and skinfold measurements. The healthy amount of body fat for men is 6-24% and for women 14-31%.
How does obesity impact life expectancy?
Obesity can impact longevity in many different ways. Developing comorbidities like heart issues or diabetes are the main and most impactful reasons your life expectancy will decrease when you're obese.
However, as obesity is a complex disease, there are other factors which can influence the average life expectancy based on weight:
- distribution of body fat,
- sex,
- age,
- diet and lifestyle,
- exercise habits,
- medical treatments.
It's known that fat surrounding your abdomen has a much worse outcome on your health than the fat on your hips, for example. When fat is layered onto your organs, they can stop working properly and cause more issues (4). Statistics also shows us that men experience a slightly greater reduction in life expectancy compared to women at the same BMI levels (5).
Being obese will seriously limit the ways in which you can move and stay functional. Obesity can also lead to the development of chronic arthritis, making it painful for you to move at all (6). Staying active at all stages is extremely important!
Interestingly, age is also a factor, but maybe not in the way you think. The impact of obesity on life expectancy is much higher when you're younger! This is because obesity will impact how your organs function, and when they are changed for the worse at a younger age, it will be harder to get their proper function back.
Talk to your doctors and see what the best treatment and strategy for you. If you suffer from an obesity comorbidity, like diabetes or high blood pressure, make sure you're undergoing treatment. Taking medication and regularly monitoring your health status is very important on your journey towards a longer life. When you take your medication, you're keep your health under check, and prolong your life expectancy.
However, the most important thing for your longevity is to work out a plan of treating the root cause of obesity. Check out the paragraph below to see how many years of life expectancy do different levels of obesity decrease.
Obesity - life expectancy chart
Based on scientific evidence, medical data, and statistics, doctors can predict the average life expectancy based on your BMI. You can find out what your BMI is by using an online BMI calculator.
These are the reductions in average life expectancies based on BMIs (4, 5):
- 18.5–24.9 (normal) - no reduction and an average life expectancy of 76–78 years for men, and 81–83 years for women,
- 25–29.9 (overweight) - a 2-year life reduction in individuals with diabetes or high blood pressure,
- 30 - 34.9 (obesity class I) - reduction in life expectancy for about 2-4 years,
- 35 - 39.9 (obesity class II) - reduction in average life expectancy for about 5-10 years,
- > 40 (obesity class III) - reduction in average life expectancy for about 8-14 years.
In recent years, two more categories of obesity appeared. Those are super-obesity with a BMI equal to or over 50, and super-super obesity with a BMI equal to or over 60. Regarding life expectancy, super-obesity results in a 10-15 years of life reduction, and super-super obesity in more than 20 years of life reduction.
This data is usually collected and analyzed by the World Health Organization and the Centers for Disease Control and Prevention. The average life expectancies are also going to change based on your lifestyle, diseases you may suffer from, and whether you're a man or a woman.
Conclusion
It's clear that obesity not only results in you developing many other conditions and diseases, but that it will significantly reduce your average life expectancy. The impact of obesity will affect you more when you're younger, and it will depend on your overall lifestyle. In extreme cases, obesity can reduce your life expectancy by 20 years or more!
Make sure to stay active, take your medication, and consider changing your diet and lifestyle. Obesity is more than just eating too much, and often underlays complex issues that are not so easy to confront. Talk to your doctor or healthcare professional, and make sure you start creating sustainable habits that fit you and help you build a long and healthy life.
Find more of our articles on longevity here:
- Anti-inflammatory Foods: The Secret to Longevity and a Healthier Life
- Lower caloric intake increases longevity - the CALERIE study
- Probiotic Supplements and Their Connection to Longevity
Literature sources:
- World Obesity Atlas 2024: No area of the world is unaffected by the consequences of obesity. World Obesity.
- Lim Y, Boster J. Obesity and Comorbid Conditions. [Updated 2024 Jun 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK574535/
- Nuttall FQ. Body Mass Index: Obesity, BMI, and Health: A Critical Review. Nutr Today. 2015 May;50(3):117-128. doi: 10.1097/NT.0000000000000092.
- Liang Y, Chen P, Chen S, Liu D, Jiang F, Zhu Z, Dong K, Wei L, Hou X. A greater ratio of thigh subcutaneous fat to abdominal fat is associated with protection against non-alcoholic fatty liver disease. JHEP Rep. 2023 Mar 16;5(7):100730. doi: 10.1016/j.jhepr.2023.100730.
- Muennig P, Lubetkin E, Jia H, Franks P. Gender and the burden of disease attributable to obesity. Am J Public Health. 2006 Sep;96(9):1662-8. doi: 10.2105/AJPH.2005.068874.
- Vincent HK, Vincent KR, Lamb KM. Obesity and mobility disability in the older adult. Obes Rev. 2010 Aug;11(8):568-79. doi: 10.1111/j.1467-789X.2009.00703.x.
- Kitahara CM, et al. Association between Class III Obesity (BMI of 40–59 kg/m) and Mortality: A Pooled Analysis of 20 Prospective Studies. PLOS Medicine. July 8, 2014. doi: 10.1371/journal.pmed.1001673.
- Prospective Studies Collaboration; Whitlock G, Lewington S, Sherliker P, Clarke R, Emberson J, Halsey J, Qizilbash N, Collins R, Peto R. Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies. Lancet. 2009 Mar 28;373(9669):1083-96. doi: 10.1016/S0140-6736(09)60318-4.
