Why is weight loss important?

Maintenance of a healthy body weight is important for maintaining both physical and emotional well-being and preventing disease. Excess weight and obesity have been associated with an increased risk for numerous medical conditions, including

heart disease,
high blood pressure,
stroke,
diabetes,
osteoarthritis,
some types of cancers,
sleep apnea, and
elevated blood cholesterol levels.

It should be noted that reduction in weight for those who are overweight can make a major impact on the conditions listed above. Many overweight people also report improved mood, increased in self-esteem and motivation, and feeling healthier in general after they have lost weight.

Source : MedicineNet