The distinction of metabolically 'healthy' from 'unhealthy' obese individuals

The prevalence and severity of obesity are dramatically increasing throughout the world. Obesity causes a decline in life expectancy due to its associated metabolic and cardiovascular comorbid disorders. Therefore, it will become more important to distinguish obese individuals at high risk for obesity-related metabolic diseases from those who are metabolically 'healthy'. This review focuses on recent evidence suggesting that normal adipose tissue function contributes to the healthy obese phenotype.

The majority of individuals with obesity develop insulin resistance, type 2 diabetes, dyslipidemia, gout, hypertension and cardiovascular disease. However, approximately 10-25% of obese individuals are metabolically healthy most likely due to preserved insulin sensitivity. Recent studies suggest that inflammation of visceral adipose tissue, ectopic fat deposition and adipose tissue dysfunction mediate insulin resistance in human obesity independently of total body fat mass. This suggests that mechanisms beyond a positive caloric balance such as inflammation and adipokine release determine the pathological metabolic consequences in patients with obesity.

Recommendations for obesity treatment should distinguish the metabolically 'healthy' from 'unhealthy' obese phenotype to identify early the obese person who will benefit the most from losing weight. In addition, novel antiobesity treatment strategies targeting adipose tissue dysfunction are needed.