Doctors and dieticians
recommend a 10% weight loss as an ideal & achievable first step. There are big health benefits in losing just 10% of your body weight! Focus on step 1 and once you've achieved it, reset your target to lose 10% more until you reach your goal...
For example
A 6ft male weighing 14st 7lbs, wanting to weigh 12st 6lbs is aiming for a loss of 14% body weight....
(Metric: A male weighing 92.1kg aiming for 78.9kg should first aim for 82.8kg, then reset the target for the final 3.5kg)