Being overweight is generally unhelpful, and it's one of those things that can be remedied without medication and at no cost.
So whether or not it helps with PN - and we all seem to have different PN - go for it.
At the risk of being obvious, no cake no donuts no fizzy drinks no crisps no beer no sweets no choc (other than one daily square of Plain) no ice cream no sugary stuff no sugar in tea or coffee no microwave meals no second and third helpings blah blah etc.

Even at my weight - 6ft/140lb - I eat little or nothing of this stuff. After a while you don't miss it, but I do miss cheese & onion crisps.