And the secret of a really good soup is the underlying stock that gives it richness and a savoury delicious-ness.

When I'm stretched for time, I used to reach for ready-made stock to make up my pumpkin or minestrone soup. Those square tetra-blocks of liquid stock are not bad - a handy fall-back when there's no time to make your own. And infinitely better than the (shudder) instant stock powder or stock cubes.

Stock is a great ingredient for anyone watching their weight. It has a tiny 1 per cent fat, few kilojoules (only 325kJ or 100 calories for a cup), significant amounts of potassium and other minerals extracted from all those bones and vegetables. Stock makes soups, risottos and gravy interesting and flavoursome.

Its only drawback is the salt. But if you make it yourself at home, you control how much salt you season it with it can be virtually none (good if you're on a low-salt diet) or just enough to round off the flavour. Interestingly this is still likely to be low compared what you get if you use a commercial stock unless you shop for one labelled "salt-reduced".

I recently took stock (pardon the pun) of my dependency on commercial stock. I've switched to making my own.

It isn't hard. You just throw everything into a large stock pot, simmer and forget. Every cookbook has a recipe gently heat bones along with onion, celery tops, turnip, a carrot and some mixed herbs. Add enough water to cover and simmer for an hour or so.

For a darker stock, brown chicken or beef bones in the oven first. The cartilage and connective tissue in the bones are the key to a rich flavour. They have collagen, which is converted into gelatin that thickens the liquid. Perfect for clear beef broth or French onion soup.

Another bonus. All those lovely vegetable off-cuts including onion skins can be used.

Cool and freeze your finished stock for later. Use containers for 2 cups or one litre or whatever is the right amount for your soup recipes.

Catherine Saxelby is a nutritionist and author of Nutrition for Life. Get more healthy eating tips at www.foodwatch.com.au