GHRL and anorexia nervosa: Accordingly, in humans, circulating ghrelin levels are generally inversely associated with weight gain, adiposity, and insulin resistance [256] and positively correlated with weight loss induced by exercise, low-calorie diet, mixed life-style modification, anorexia nervosa and cachexia due to chronic obstructive lung disease (COPD) or chronic heart failure (CHF) [71,257,258].