Breakfast: Boiled potatoes with some seasoning
Lunch: Boiled Potatoes w/ seasoning and Kim Chi (pickled Korean cabbage...zero fat)
Dinner: Mashed potatoes with a couple tbsps light soy milk and salt and 1 cob of corn.
In the MWL book, McDougall talks about filling at least 1/3 of your plate with green and yellow veggies (corn would not count, that's more of a starch) at each meal. You can up that to 1/2 of your plate if your rate of loss is still too slow. I think you will see quicker success if you majorly up your intake of raw and steamed green and yellow veggies (think romaine lettuce, cucumber, celery, carrot sticks, peppers, onions, mushrooms, cabbage, etc.).
I'd definitely recommend reading his articles on the Maximum weight loss plan, as well as the one on lowering your set-point as that will give you a lot of pointers about how you can tweak things to maximize weight loss.
You might do just fine losing weight on the above menu plan though. You just asked for suggestions, so i'm offering. Also, I'm assuming the "seasonings" contain no oil? And yes, the soymilk is not MWL, so if you find you are not losing, it might help to eliminate even that little bit.