Hello welcome to HCM
i would like to know the duration of your latest period since 'till today'date is not specified (today is 30 nov 2013).
1. as per your age ,you may be close to menopause
,in which case variability starts in duration/amount of bleeding/pain etc.
2.change in diet will not affect periods.
3.you may also want to get a thyroid
function test done ,if there is weight variation/intolerance to hot/cold climate/lethargy
4.keep up a routine of healthy balanced diet ,exercise,low stress
hope you get a good guideline by this .