Yeah, I'm the same way, almost allergic to everything. Your resting pulse is what you feel for before and after you eat/drink something suspect. Get really comfortable for 5 minutes before testing you pulse. I tested at the neck before I bought a $15 finger tester on EBay that is quick and easy. If anything is tight on your body (underwear, shoes, etc) you have to loosen or remove it. All physical stress elevates the pulse. Your true baseline pulse is what it is in the morning before getting up (if you aren't allergic to your bedding or pillow). Anything that increases your pulse by 6 beats per minute is allergic to you. Your pulse speeds up as your whole body speeds up to hasten the removal of the offending substances from your body. That speeding up tires you out. But until you start getting more exercise you will also feel more tired by eliminating the offending foods because they act as stimulants like coffee or sugar.