Mixed
Class III obesity (BMI 40.0–59.9 kg/m2) is associated with substantially elevated total mortality and major reductions in life expectancy (6.5 to 13.7 years lost) compared to normal weight, primarily driven by increased risks of heart disease, cancer, and diabetes.
If you have a BMI between 40 and 60, your risk of dying earlier is significantly higher than someone with a normal BMI, costing you an average of 6.5 to 13.7 years of life. This risk is driven largely by heart disease, cancer, and diabetes. The risk increases as your BMI gets higher within this range. While individual outcomes vary, the population data is clear: reducing BMI towards the normal range is associated with regaining these years of life.
Class III obesity is associated with substantially elevated rates of total mortality, with most of the excess deaths due to heart disease, cancer, and diabetes, and major reductions in life expectancy compared with normal weight.
Why this rating
Large pooled analysis of 20 prospective studies with over 300,000 normal-weight and 9,500 obese participants, adjusting for multiple confounders.
Source
Association between Class III Obesity (BMI of 40–59 kg/m2) and Mortality: A Pooled Analysis of 20 Prospective Studies
Cari M. Kitahara et al. · PLoS Medicine · 2014
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