I would have thought that the load on the heart for digestion is quite considerable. When I was doing heavy labour tasks in the building trade, like mixing 6 tons of concrete over several hours using a shovel, all I experienced was mild chest pains. Once I ate a meal, it was MI time for 20 minutes.
After a meal the digestive organs require considerably more blood/resources than they do when not actively engaged in the process of digestion. This of course diverts blood away from other major organs. I would expect to see a temporary increase in BP and heart rate as part of the body's mechanisms to meet the interval needs of the digestive organs while still maintaining steady resources to other vital organs. I'm not sure how much rise to expect after a meal but a 20% variation throughout a day isn't unusual.
BP is also often higher in the morning after arising and assuming a vertical position. It may rise as the mind becomes more active in planning the day. Any BP medication you take is likely at it's lowest blood concentration level in the morning hours (just before the next dose is due). I have heard that more heart attacks occur in the early morning hours than at any other time.
After eating, your heart works harder to send blood to the organs that are digesting your food which does increase your heart rate and blood pressure, not usually a large amount but it is noticeable.
Jon