Is It True That A Child Eating A Bag Of Crisps Every Day Consumes 5 Litres Of Cooking Oil A Year?

Well, maybe, maybe not.
It depends how big the bag of crisps are, and how it's cooked.  Some types of crisps are made in less oil (lite versions), too.

You might to wonder how bad cooking oil is, anyway.  Cooking oil can be a minimally processed blend of oilseed rape, sunflower and safflower oils.  Does that sound so bad?  Especially for fast-growing active children who don't have lots of other high fat sources in their diets?  Or cooking oil might mean hydrogenated fats, which are full of trans fats which are strongly linked to heart disease.

I did my own numbers after i heard the 5 litre figure, using bags of McCoys Cheese and Onion, leading supermarket's own Salt and Vinegar, and Hula Hoops.  Daily McCoy's definitely would lead to the 5 litre figure.  But on my numbers a child eating one of the other bags of crisps most days from their school lunchbox gets just over a teaspoon of oil per day (not a tablespoon full).  And that works out to about 1.5 litres of fat a year.

I don't know how much litres of oil consumes but, more crisps the child eats, the more health problems occur.