I love chips and I want an expert to say that they’re not ridiculously bad for me. Surely they have some redeeming features? After all, potatoes are vegetables.
S Weaver, by email

The nutritional content of chips varies depending on what they’re fried in and how chunky they are. Frying in lard, for instance, increases their saturated fat content, whereas using a seed or nut oil is healthier. Using the same oil over and over, as some fast food restaurants reportedly do, can increase their trans fatty acid content. Trans fatty acids are more damaging to health than saturated fats.

Thinly cut chips have a greater fat content, weight for weight, than fat-cut chips because their greater surface area causes them to absorb more fat. So chunky chip-shop chips are better than French fries. On a positive note, potatoes retain a little more vitamin C when fried rather than boiled, and they can be even better for you if you add a flavouring such as paprika instead of salt.