Why should I encourage rest before/after meals to pts?

I am in my first semester of nursing school and for my first care plan my teacher said I should encourage rest before and after meals to a pt who is going through chemotherapy and has a nursing Dx of "Imbalanced nutrition: less than body requirements" and has severe nausea and vomiting. Can someone elaborate?
Just taking a guess, but maybe because motion aggravates nausea. The last thing you want to do when you're nauseated is get up and walk around.

Also, chemo wears you down. Sometimes, the act of eating is tiring. It's important to get as much rest as possible.

Thank you! Both ideas make sense.

I would think because of the imbalance, less than body requirements... meaning calorie/nutrition intake being low...the patient needs to conserve calories consumed and not increase calorie burning. that's the only way I can think of it directly relating to that nursing diagnosis.

because the act of digesting food alone takes up a lot of energy. For a pt who already has no energy and is on chemo, eating and then doing an activity will be very draining. They're going for spacing out activities and not doing multiple ones at the same time. Hope this helps!

Also if you remember your A&P, after one ingests food, the parasympathetic nervous system kicks in. You body diverts blood to your innards and goes into 'rest and digest' mode. If you ask it to do exercise, your resources are limited, and as you know, this persons resources are already limited.

Putting Sanuk and StephanieRNs ideas together, you want to prevent nausea, because vomiting will further decrease the patient's nutrition, which is already less than body requirements.