Lately, I seem to have been rather bogged down with rear-ends.

Judging by readership response, it may be a good idea to go into more detail about how to make the digestive machinery function like clockwork or, at least, as regularly.

In the world of nutrition, constipation is a dirty word. If you let slip you are a sufferer, you will be subject to much tut-tutting and dire predictions ranging from bad breath, headaches, skin complaints, flatulence and piles to varicose veins.

If this isn't bad enough, you are then regaled with endless remedies and dubious concoctions which taste about as good as they look.

If you are concerned you maybe constipated, do a simple home test to find out your bowel transit time.

Transit time is how long it takes from the time you eat your food until it reappears again, albeit in disguise.

Get some corn on the cob, eat it and note down the date and time. The corn serves as your marker, so watch your bowel movements until you spy the kernels.

By calculating how many hours since you ate the corn, you arrive at your individual transit time. This test can also be done with whole red beets (watch for stools turning red). Great topic for stagnating dinner parties this Christmas: "I'll tell you my transit time, if you tell me yours!"

A healthy transit time is 18 to 24 hours. Less than twelve hours means that you may not be absorbing all the nutrients from your food.

More than 24 hours means waste and toxins are accumulating inside your intestines and harmful substances may be re-absorbed.

The longer digested food lodges in your passageways, the more difficult it is to expel. Reasons for constipation include nervous disorders, food intolerances and obstruction of the large bowel. Long-term use of laxatives encourages dependency and does not deal with the root cause of the problem.

Frequently, the reason is simply a lack of fibre coupled with a lack of exercise.

Fibre provides bulk and retains water in our stools for easier passage, exercising the muscles of the large intestine and mopping up toxins on the way.

Fibre also nourishes our good gut bacteria, helps to lower cholesterol and regulates blood sugar levels.

The refining of food causes heavy fibre losses, increasing the risk of digestive diseases and contributing to diabetes and heart disease. Best food sources, therefore, are fruit, vegetables, whole-grains, pulses and nuts.

Try prunes and figs before and after meals, or psyllium fibre if well and truly stuck (from health stores).

But do be wary of increasing your fibre intake too rapidly - your body needs to adjust to any change in dietary habits.

Wheat bran can be a useful aid, although some people find it makes them worse - oat bran or flaxseeds may be easier to digest (mix 1 tbsp daily into your yoghurt or muesli and ensure high intake of fluids).

Fibre okay keeps the doctor away - an easy, cost-effective way to reduce the risk of degenerative disease!