Willpower is a limited resource, environmental modifications and behaviourism are king here. Find ways that work for you to keep less food around. Count calories, and reinforce meeting your calorie goals each day. If that doesn't work, it doesn't mean you are weak or bad, you just haven't found something sufficiently reinforcing yet. You can experiment with reinforcement intervals. Don't be afraid to start off with over-the-top reinforcement, you can always fade it down the road. But there's no substitution for calories in/out, there's no way you can get around eating less food if you want to lose weight (unless you exercise a ton, but that's typically not sustainable for someone chronically overweight).