I would wager to say you've been doing it incorrectly all these years, honestly. The REASON you want to have a low fat diet before testing is SO THAT food is NOT a variable in the equation for basal testing. IF you eat foods high in fat, or protein, those foods take longer to process and are in the system much longer. This skews the results of any testing you do to dial in his basal because the "effects" of the food are still in the system. The PURPOSE of basal testing is to test the system WITHOUT any food affecting the results.
Once we have the basal rates set correctly, BY following medical recommendations for testing that basal (eat a meal 4 hours prior to beginning that is low in fat), we can THEN adjust his mealtime bolus requirements after the basal is finely established.
No one is "restricting" anyone's diet...it is ONLY for testing purposes, WHICH IS RECOMMENDED. If you haven't followed that medical advise, then I would say your tests have all been inaccurate. My son can, and will, go right back on those foods he knows and loves when the basal test(s) have been done. The low in fat is ONLY so that we can get an ACCURATE basal test completed. We're concerned our tests to now have not been accurate because the requirement to have foods low in fat has not been met by us yet. And THAT was the reason for this thread/discussion, was to ask whether these foods I'm using are good choices for a basal test. I know that they are NOT now, after doing some other research so I'll adjust accordingly to ensure I'm doing the BEST possible test I can for my son. And there will be nothing "unfortunate" about it for my son - the goal is to IMPROVE his quality of life -- and this is a very FORTUNATE thing for him, and for our family.
But I only know what I've read...from medical professionals. What do I know.