McDonald's Big Mac is made of two all-beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
The ingredients for each of these are:
beef patties
Two 100% whole beef patties (although I'm not sure what they consider beef)
the sauce
water, vegetable oil, gherkins, sugar, vinegar, modified corn starch, egg yolks, spices, fructose, salt, stabiliser (E415 xanthan gum), preservative (E202 potassium sorbate), spice extracts
the lettuce
100% pure shredded iceberg lettuce
the cheese
vegetarian cheddar cheese, water, butter, milk proteins, natural cheese flavouring, emulsifying salts (E331 trisodium citrate, E450 diphosphates, E452 polyphosphates), lactose, salt, preservative (E200 sorbic acid), colour (E160(a) carotenes, E160(c) paprika)
the pickle slices
cucumber, vinegar, preservative (E210 benzoic acid, E327 calcium lactate or E200 sorbic acid and E509 calcium chloride), spices
the onions
100% pure dehydrated white onions
the bun
flour, water, sugar, sesame seeds, rapeseed oil, yeast, salt, soya flour, emulsifier (E472(e) mono- and di-acetyltartaric acid esters of mono- and di-glycerides of fatty acids), preservative (E282 calcium propionate), flour treatment agent, E300 ascorbic acid
The typical Big Mac will contain:
Energy(Kjoules).......2050.0
Energy(Kcalories.......493.0
Carbohydrates(grams)....44.0
- sugars(grams).........11.6
Protein(grams)..........26.7
Fat(grams)..............22.9
- saturates(grams).......9.8
Fibre(grams).............5.3
Sodium(grams)............0.9
Source: Schott's Original Miscellancy