When Can I Start My Normal Diet After Gastrointestinal Stromal Tumor Removal?

I had 1/4 of my stomach removed approximately a month ago to remove a Gatrointestinal Stumor Tumor. I was told not to eat certain foods for a period of time, i.e. nuts, lettuce, beef, chips, primarily sent home on a soft food diet. I was just wondering how long before one can start putting things like nuts, lettuce, beef, chips and such back into your diet.