One of the concerns of health professionals has been obesity and the health complications that are associated with it. An increase in BMI was thought to have effects on diabetes and heart disease. However recent studies are coming out that dispel these myths. In a review of 40 studies and 250,152 people, it was found the rate of both total mortality and mortality to heart disease for overweight persons was lower than people of normal weight. This is known as the ‘Obesity Paradox’ and raises questions on the validity of weight loss for health.
Protective Factors of The ‘Obesity Paradox’
This paradox is not just restricted to heart disease. Obesity has also been shown to be a protective factor against:
- Peripheral arterial disease
- Postoperative complications in patients after cardiac surgery
- Complications during catheter ablation for atrial fibrillation
- In-hospital mortality in surgical intensive care unit
- Type 2 diabetes
- Amputation risk among nonelderly diabetic men
- Chronic obstructive pulmonary disease
- Hemodialysis patients
- Critically ill patients
One important thing that is should be considered is ‘weight loss and not weight gain was associated with increased morbidity and mortality during the mean follow-up of 34.5 months’. Weight loss not weight gain is associated with an increase in death.
Factors contributing to the ‘Obesity Paradox’
There are some factors that are adding to the ‘Obesity Paradox’. Some of the factors may include:
- Age – Studies around visceral adipose tissue (VAT) demonstrated that the amount of gained visceral fat decreases with age. One study measured the VAT of nondiabetic Japanese American men and women aged between 34–74 years. They found that the accumulation of intra-abdominal fat over 10–11 years was significantly greater ages 34–43 years compared with people aged 54–63 years. There was no difference between the sexes and their association with weight gain.
- Medical treatment – Obese patients may have better medical treatment than normal BMI patients
- Body Composition – In a study of men and women aged between 62–66 years, it was found that BMI was a better measure of lean body mass than of weight gain. This lean body mass is thought to be more favourable to changes in prognostic factors that predict of mortality among patients with heart disease compared with adipose tissue. It has also been hypothesised that a decrease in BMI could attributed with “malnutrition-inflammation complex syndrome” .
- Enlarged muscle mass and better nutritional status – Higher mortality in people with low BMI may be due to obesity that is characterised by low muscle mass. Many obese patients have an increase in muscle mass with the increase in fat mass.
- Ghrelin Sensitivity – Growth hormone release is stimulated by Ghrelin (hunger hormone) increasing food intake which also promotes positive energy balance/weight gain. This has been shown to improve the way the heart contracts
Other factors include: Cardiorespiratory fitness, increased muscle strength, mobilization of endothelial progenitor cells, thromboxane production, increased production of inflammatory cytokines.
With all the evidence stacked in the favour of the health of overweight and obese patients, is it justifiable to expect them to lose weight? Or have we been conned by our ‘Thin’ and ‘Diet’ culture that thin is healthy? We know that 95% of diets don’t work and that the body has a ‘set point’. If that ‘Set Point’ is in a BMI greater than 25 this research gives us comfort that we are still healthy and that there is no requirement to lose weight.
Vojtech Hainer, Irena Aldhoon-Hainerová, ‘Obesity Paradox Does Exist’, Diabetes Care. 2013 Aug; 36(Suppl 2): S276–S281