Sweats..

I'm a man almost 42 years of age, overweight (i'm 5'11 and weigh 15.5st) non smoker. For as long as I can remember i've sweated when i've eaten, i've always thought it was maybe a salt intolerance, as its often worse when i'm eating salty/spicy food. I've also found that i'm having night sweats too. Its hot at the minute but this happens in the winter also. Does anybody else suffer from this embarrassing condition and if so is there something I can do to change the situation ? Is it something I should be worried about ? Its driving me mad as I like to dine out with my wife but i'm starting to get self conscious about it. Hope somebody can help, my doc has tested me for diabetes and i'm not diabetic and all he could suggest was I cut down my salt intake, truth is I never add salt to my food !