These days we know quite a lot about fats. We know, for example, that Western diets contain too much in the way of saturated fats. Saturated fats come mainly in dairy products like cheese and butter and we know these aren't good for us. Perhaps less well known is the fact that saturated fats are in probiotic full-fat yogurts and even in intensively farmed animals where they have a significantly higher ratio of saturated fat to protein.

Processed food should be another no-go area. By...