Medicine doesn't work if you don't take it
And the same applies for all interventions. Most of us stop things once we have reached our goal. We stop driving lessons once we have passed the test for example.
So, if you have managed to lose weight, keep on with the treatment. Otherwise the weight will come back on again as soon as you stop, unless you change your eating patterns (which would count as a new intervention). Most dieters regain the weight they have lost. Depressing thought.
Hypnosis helps with making the behavioural changes necessary for a lower weight. To lose weight, we have to eat less, and hypnosis helps us with sticking to the plan. How many calories do you need to eat to maintain your current weight? This tool will give you an estimate. http://www.cancer.org/healthy/toolsandcalculators/calculators/app/calorie-counter-calculator. When you know roughly what maintains your weight you can look at what would maintain a lower weight. That could be the start of a plan.
Making small changes to our lifestyles makes it more likely we will gradually adapt to more helpful eating behaviours for ever. And hypnosis gives just that bit of extra support to help us keep on track.