This is the easiest and most common method, but by far the least accurate, as it only measures one quantity (weight) and often does not take into account many factors such as height, body type, and relative amount of muscle mass.Skinfold calipers or "pinch test"The skin at several specific points on the body is pinched and the thickness of the resulting fold is measured. This measures the thickness of the layers of fat located under the skin, from which a general measurement of total amount of fat in the body is calculated. This method can be reasonably accurate for many people, but it assumes particular fat distribution patterns over the body—which may not apply to all individuals, and does not account for fat deposits not directly under the skin. Also, as the measurement and analysis generally involves a high degree of practice and interpretation, an accurate result requires that a professional perform it. It cannot generally be done by patients themselves.Bioelectrical impedance analysisA small electric current is passed through the body to measure its electrical resistance. As fat and muscle conduct electricity differently, this method can provide a direct measurement of the body fat percentage, in relation to muscle mass. In the past, this technique could only be performed reliably by trained professionals with specialized equipment, but it is now possible to buy home testing kits that let people do this themselves with a minimum of training.
hypothyroidism)
Insufficient or poor-quality sleep
Limited physical exercise and a sedentary lifestyle
Poor nutrition
Metabolic disorders, which could be caused by repeated attempts to lose weight by weight cycling
Overeating
Psychotropic medication (e.g. olanzapine)
Smoking cessation and other stimulant withdrawal
StressPeople who have insulin dependent diabetes and chronically overdose insulin may gain weight, while people who already are overweight may develop insulin tolerance, and in the long run develop type II diabetes. Treatment
The usual treatments for overweight individuals is diet and physical exercise. Dietitians generally recommend eating several balanced meals dispersed through the day, with a combination of progressive, primarily aerobic, physical exercise. In fact, some research found benefits from physical activity, diet and behaviour changes on BMI in children from 12 to 17 years old.Considering that most of the treatment strategies are directed to change lifestyle-related behaviours of individuals (namely in dietary and physical activity), the transtheoretical model (TTM) has been used as a framework to design weight management interventions. A systematic review assessed the effectiveness of dietary and physical activity interventions based on the TTM in producing sustainable (one year or longer) weight loss in overweight and obese adults. The included studies did not allow to produce conclusive evidence about the impact of the use of this model combined with these interventions on sustainable weight loss. Nevertheless, very low quality scientific evidence suggests that this approach may lead to improvements in physical activity and dietary habits, namely increased in both exercise duration and frequency, and fruits and vegetables consumption, along with reduced dietary fat intake.