You'll get a letter and a voucher from SW head office for a free week when you've kept that weight off for 10 weeks, and hopefully you'll have lost more weight by then too!
Aparently there are at least 10 benefits to losing that first 10% -
These include reducing the risk of high blood pressure, heart disease and stroke, weight loss could reduce any risk of developing diabetes, lower cholesterol levels, reducing strain on joints and improving back and joint pain, better lung function, reducing breathlessness, improving mood and self-esteem, improving any asthma symptoms, improving mobility, improving fertility, reducing risks of cancers!