I purchased a wrist bp monitor (needed for hubby). The instructions are very strict about when it should be used.
Not just after having eaten, drinking tea/coffee or any form of exercise, even walking.
Patient must be relaxed, and pulse/bp taken ideally at heart level.
When taken by GP at the surgery, it is given the term "white coat syndrome" because the patient has only just sat down, possibly walked to surgery, is agitated regarding their visit to the doctor!
I tested this myself, by walking about, taking my bp/pulse then relaxing for 10 mins, taking reading again - and there is a marked difference.
So don't be undully alarmed at this as eating is a contributory factor.
(Dr) Jeep Lol :o)