The meal I suggested is not good for someone with diabetes, I realize now. I am sorry.
Paracelsus said: your food should be your medecine.
Is there anything a person with diabetes can eat in large amounts and at the same time improve his shape ?
It cannot be fat (although there is some Atkinson diet which is based on fat) and it cannot be protein.
There is nothing you can eat in large amounts that will help your shape.
In the end it's all about calories. You can't change the laws of physics captain, and the second law of thermodynamics is one of them.
There is one thing you might try. The calorific difference between your food and your excrement is the amount of energy you consume. If you want to consume less and eat the same you will have to increase the calorific content of your excrement.
We tend to have trouble extracting calories from raw food such as carrot. So eat more raw food.
The idea about eating more fermented food will not help in this respect as it is already pre-digested, which facilitates the uptake of calories.
The trouble with eating low-calory-availible foods such a raw carrot is that the feeling of fullness is mainly due to the amount of blood sugar, which will be lower with such foods. So whilst you can feel full you still have a sense of hunger, which needs to be trained away.