Food manufacturers and supermarkets use many tricks to persuade you to part with your cash and choose their product rather than someone else's. But there are also laws that they have to abide by.
Here is Gregg Wallace's handy guide to avoiding the tricks of the trade and understanding the law. If you read this, you will be on your way to being label savvy.
RULE ONE: LOOK BEHIND THE PACKAGING
Do not believe everything you see or read on the front of the pack. Firms use food packaging as a sophisticated selling device to market their goods, like a mini billboard.
Photos are slapped on everything from soup to cereals. But are they really helping us see what we are getting?
Will the ready meal look appetising when it is served?
It is illegal for photos to actually mislead. But trading standards officers say the term misleading can be rather subjective.
Assume companies are showing goods in their best light. When you dish it out in the cold light of day, it might not look quite so tempting.
Beware of symbols, icons and images that suggest a product is healthy - like ticks, or fields of wheat, or leaping figures.
Your eye is being told the product must be good for you, and must be fresh or natural. In fact, the product may be mass-produced and high in sugar or fat.
RULE 2: ALWAYS READ THE SMALL PRINT
You may need to get your magnifying glass for this rule, but if you want to eat healthily, you will need to read the ingredients list.
Ingredients are listed in order of weight. At the top of the list are the items which the product contains most of, at the bottom those it contains least of.
This can help you judge the quality of a product.
The label will tell you how much pork is in the sausage
Sometimes the amount of a particular ingredient has to be listed. For example, pork sausage labels have to state the percentage of pork in the sausage. They must contain at least one third pork but a high quality sausage will have much more.
And if one ingredient is highlighted in a picture on the packet, then the ingredients list must tell you how much of that ingredient there is in there.
If you are trying to cut back on sugar, do not just look for the word sugar.
It is worth checking the ingredient lists for any words ending in "ose" - dextrose, sucrose, glucose, fructose are all different kinds of sugars. They can be listed separately so it may look as though there is not much sugar in a product when in actual fact it is full of it.
And as for those additives and E-numbers - they are all there for a reason. They might be flavouring, colourings, thickeners or preservatives. The product would not taste the same or last as long without them.
Some E-numbers come from natural sources, others are laboratory produced but by law they must all be listed.
There are some you may want to watch out for as recent research has found a possible link to hyperactivity in children. These are generally found in cakes, sweets and fizzy drinks: Sunset Yellow (E110), Tartrazine (E 102), Carmoisine (E122), Ponceau 4R (E124 - banned in the USA), Sodium Benzoate (E211) Quinoline Yellow (E 104) and Allura Red AC (E 129)
RULE 3: DECODE THE JARGON
Some words used by the food industry are protected by law. For instance if you buy chocolate or bread, fruit juice or jam, you should be reassured that they must contain certain amounts of key ingredients.
But watch out for variations on these names: something described as "chocolate flavoured" means it does not qualify as chocolate.
Fruit juice drinks contain less fruit than pure fruit juices
"Fruit juice drink" does not have as much fruit in it as pure fruit juice, and will have more sugars, sweeteners, colours or preservatives. The Food Standards Agency (see links on the right-hand-side) has the latest details on what qualifies as what.
It can get complicated: "Strawberry yoghurt" must have real strawberries in it. "Strawberry flavoured yoghurt" must have flavour made from strawberries, but "strawberry flavour yoghurt" has artificial flavourings and has never been near a real strawberry.
But you cannot always read very much into a name.
We discovered that Marks and Spencer's Oakham chicken for example does not come from Oakham - and that is perfectly legal.
RULE 4: KNOW YOUR NUTRITION
Supermarkets have recently introduced new front of pack nutritional labelling schemes.
They are supposed to help you understand how much salt, sugar and fat there are in the things you buy. The problem is there are two different schemes backed by different supermarkets, and they are both quite tricky to understand.
The Traffic Light System backed by Sainsbury, Asda, Waitrose, the Co-Op and Marks and Spencer puts four traffic lights up on the label.
They are green, amber or red to indicate whether that product is low, medium or high in fat, saturated fat, salt and sugar. The colours are based on the percentage of fat, sugar and salt in each 100g.
The Guideline Daily Amounts (GDAs) system, backed by Tesco, Somerfield, Morrisons and many food manufacturers, looks at each serving and show what percentages of your recommended daily total of sugar, salt, fat and calories that serving contains.
The government is currently doing more research to find out which system works better - but for now, you might feel you have to brush up on your maths if you are going to get your head round both systems.