You can eat as many or as little meals as you like.
Home made crisps are synned even when made from free fry light and potatoes because by having potatoes made that way you are likely to eat more than you would if you had them baked, boiled or mashed. Chances are, if you had a 200g baked potato you'd think it was pretty big, especially if you had with with a filling and some veg. But I reckon most people could easily get through 200g of crisps while watching telly without noticing.