Psylent...This happens to me and my hubby when we eat. If we eat a large meal that we love, our heart rates go up (yes, we both have high blood pressure that is controlled). Our BP is fine till we eat the big meals. We've been told this, when a large meal is digested, your body is focusing on the job entailed (which is digesting all that food sitting in there). So, all the focus your body is working on is digesting that food and doing its job. After the food passes, your blood pressure will be coming down. Now why

do we do that to ourselves to begin with? Because it tastes good. It's an indulgence. But does our body like to work that hard? It's doing what it needs too. I think the body would work a lot less if we worked it harder with exercise, so that a big meal didn't overwork it.
If it worries you that much than eat smaller portions in intervals.