A lot of foods that are high in fat or sugar, like deep-fried foods and biscuits, can cause high heart rates and skipped beats in some people. I personally can't eat a lot of sugar at once without feeling my heart do strange things. Another food trigger for me is MSG ... which is found in far more foods than you'd think. MSG is responsible for a number of health problems, so I'd suggest you check the ingredients on foods that make you feel these symptoms, and see if it could be the culprit. As for the nuts, though, that surprises me. Although they're high in fat, it's a healthy fat that should make you feel good, not bad. It could indeed be a food allergy, like Jerry says, and more difficult to diagnose. Still, if you avoid the sugar and the fried foods, you should be on the path to feeling better.
Just guessing, the nut connection could be a food allergy, some people have very serious reactions, even death, from eating nuts. In the USA there has been a move in recent years to never "hand out" nuts as snack food on airlines (well truth is no free snack in coach class anyway - but I digress). The rich food connection may be similar.
If you know what causes a problem a good strategy is to avoid the causes.
I suffer from atrial fibrillation, permanent. This causes me to have a higher heart rate and an irregular one. I take beta blockers to slow the HR down.