I know this is a very common question and I have researched both on here, and elsewhere a lot!! My situation however seems slightly different in so much as it happens almost immediate, within just a few minutes of eating. It is not so much "tiredness" but more of a fatigue / brain dead sort of feeling.
I have had lots of blood tests from my GP that have all come up with no issues. These included blood sugars, thyroid, anaemia, vitamin deficiencies etc etc =- all clear.
It has been going on for a couple of years, but is not getting worse.
I have tried all the usual, cutting out dairy, cutting out glucose, cutting out carbs etc, to no effect at all. It doesn't seem to matter what I eat, but it is related to portion size. I currently eat very small potions to limit the effect, but it is still there and "gets in the way of my life".
Age = 65. Otherwise healthy. Slight "beer gut" but not obese. I eat healthy food. I get a fair bit of out doors exercise.
I think the interesting bit is that it comes on so very quickly.
Any thoughts / comments appreciated.