The advice was unanimous. If you are flying long distances, eat as little as possible and drink as much as possible. (The last part of this advice was spoiled by a caveat: no alcohol.)

I did the opposite. I ate everything that was put in front of me, and drank only the minimal ration of fluid that came with each meal. This was a mistake. I should have taken the advice. That’s why I arrived in London feeling less than sharp. Not ill exactly, but slightly queasy. And it wasn’t all jetlag and dehydration. More than anything, I think it was the food.

Here’s what I ate, with each meal and snack rated on a scale of one to five.

Chicken and brie focaccia sandwich (Canberra Airport snack bar, midday).  The two slices of focaccia bread were lightly toasted. Between them were pieces of roasted chicken, with brie that had melted under the heat of the toasting process, plus shredded basil leaves. The chicken retained some remnants of moistness. The brie was warm, bright yellow, and runny, but luckily there wasn’t too much of it. What lifted this snack was the sharp and delicious hint of basil. The toasting gave the bread a pleasantly fine veneer of crispness. This snack was well above the average, but from here it was all downhill. ★★★★✩

Ginger muffin (Qantas in-flight snack, mid afternoon between Canberra and Sydney) The flight from Canberra to Sydney takes 40 to 50 minutes, so there is scarcely time for the stewardess to drop a cardboard box in your lap before she is back again, hovering, ducking, leaning, trying to grab back what she has just given you, suggesting you stuff the remnants of your snack into a kind of sick-bag that comes with it. Inside the cardboard box lies a puffed-up tennis ball of cellophane with a brown object inside – a ginger muffin. The muffin is quite moist, very sweet, speckled with tiny currants and carries a strong, almost smellable, flavour of ginger. Edible, but only just. ★★✩✩✩

Vegetarian pasta (British Airways dinner, early evening between Sydney and Bangkok) The main course came with an entrée of coleslaw salad (not bad, fairly crunchy) and a dessert of white mousse (nice and light but ultra sweet). Peeling back the aluminium foil on top of the main dish revealed a mini-swamp of macaroni in white sauce. Green peas decorated the surface, like frogs talking a quick breath before diving, and fragments of red carrot floated here and there like discarded Coke cans. Inserting a plastic fork revealed that the sauce had congealed. You could lift the contents of the dish to your mouth in grainy lumps. The flavour was bland. ★★✩✩✩

Pastrami roll (British Airways snack, served around midnight prior to stopover in Bangkok) The slice of dark pastrami beef – wiped with a blackish mustard – lay between two halves of a bright white, floury-crusted, sourdough bread roll. The meat and mustard tasted OK, though neither looked very appetising. But the bread was a disaster: stale, tough and flaky. ★★✩✩✩

Braised pork with rice (British Airways dinner, served in the small hours of the morning after departure from Bangkok) The pork squirmed at the right hand end of the small dish, jostling with rice in the middle and vegetables to the left. The pork was truly horrible, almost unrecognisable as meat, with a kind of unpleasant, slightly bitter bite in its flavour. The rice was mushy. The vegies were grossly over-cooked. After eating this concoction I reached with gratitude for the dessert, a Kit Kat chocolate bar. And a small bottle of Spanish tempranillo wine was smooth and generous enough to erase the barbaric after-taste of the pork. No stars for the food though. ✩✩✩✩✩

“English breakfast” (British Airways, served at 4.30 a.m. on approach to Heathrow). Two kinds of breakfast were on offer, “Omelette” and “English”. I chose the latter, but glancing surreptitiously around I concluded that the two breakfasts weren’t much different. Mine had a chicken sausage, half a fried tomato and some rather slimy brown lumps which were probably champignons although they had no recognisable flavour. The main component of the meal was scrambled eggs between two slices of ham. The ham was excellent – lightly cooked and quite flavoursome – but the scrambled eggs had been pressed into a block that could be lifted en masse like a small brick. A tiny serving of diced fruit delivered some freshness to the mouth at the conclusion of the meal. ★★★✩✩

So… looking back over my nutritional intake during those long 24 hours, I think I know why I saw Heathrow swaying slightly through a filmy haze.

Morgan Spurlock’s film Super Size Me documents the drastic effects on his physical and psychological health of one month spent eating nothing but McDonald’s food. Morgan… for your next act, try 24 hours locked into an airline diet. The food wasn’t all bad news, but it was mostly bad news.