Health foods are currently the big success story in food retailing.
Organic food is now big business
Organic produce has been increasing in popularity with sales up by nearly a third every year, for the last 10 years. In the UK, we are now spending around £37m a week on organic food.
These increases have coincided with people becoming disillusioned due to food scares such as BSE, and bird flu. More people want know where their food comes from and what is in it.
Stories about the increasing levels of obesity in Britain, public health messages such as the need to eat at least five - or even nine - portions of fruit or vegetables a day are also encouraging people to take more interest in their food. And television makeover programmes, showing people changing their lives by changing their diets, are having an effect.
Food retailers such as supermarkets have picked up this public interest and are increasingly providing people with healthier, or lower-fat versions of the foods they like, such as cheese, milk, ready meals and cakes. Tesco is the leader in the field with over half of this £1.5 billion a year market.
The other growing area is food which does a bit extra, because it has had things added.
Foods with things such as Omega-3, pre- or pro-biotics, or plant sterols to help bring down cholesterol levels are all called "functional foods".
You can buy milk, yogurt and even bread, with added Omega-3, normally found in abundance in oily fish. It is claimed to be good for children's brains, although the more accepted claims are that it is important in making healthier hearts.
The benefits of superfoods are still under debate
Pre and pro-biotics are often added to yogurts and yogurt type drinks and are said to be good for stomach problems, although some dieticians say most healthy people do not need them. They argue that most people would do better to get the nutrients from eating a balanced diet rather than added extras.
But the functional foods market continues to grow and is expected to increase from around £1 billion a year to around £1.2 billion, by 2011.
How super is super?
Another growth area is so-called "superfood".
Foods such as broccoli, apples or kale have been described as superfoods, as have more exotic foods, such as goji berries, blue-green algae and wheat grass, because they all provide a lot more nutrients than many other foods.
But many dieticians say there are no superfoods, only super diets.
They say the nutrients such as anti-oxidants that superfoods have in a particularly high concentration cannot be stored by the body and are flushed out: so it is better to have a little and often, rather than a lot in one go.
They say an apple a day may be better than a bag of expensive goji berries once a month.
But calling something a superfood is in any case likely to become less common due to new European legislation which requires food manufacturers to prove any claims they make about their food.
So, if a food is described as making you healthier or living longer or improving your eyesight, there will need to be scientific evidence to show this.
What's Really In Our Food? was broadcast from Monday 26 to Friday 30 November 2007 at 0915 GMT on BBC One.