What constitutes a healthy breakfast? It is a topic which bears close inspection during National Breakfast Week, with experts falling into two distinct camps. About the only thing they agree on is that having any breakfast at all is a Very Good Thing.
The eggs, cheese and yoghurt fraternity points out that protein makes you feel full for longer and stabilises blood sugar. Yet 97 per cent of British households keep a box of cereal in the house and two thirds of us raid it at least once a week. Cereal is cheap, quick, and qualifies for many as comfort food.
Porridge is the latest fast food to hit the high street, while new super-varieties like Morning Glory - which contain four other grains and five seeds besides the oats - are invading the supermarkets. However, while oats have a valuable part to play in combating high cholesterol, most commercial cereals have been in the dock for decades.
They may no longer contain as much sugar or salt as they used to - and can be a good source of folic acid and B vitamins - but the fast-energy fix a carb-laden breakfast can produce is a bad thing in the eyes of many nutritionists.
"Most cereals, even the ones that don't contain any added sugar, are high on the glycaemic Index, so they can raise blood sugar as fast and to the same degree as eating pure sugar," points out Mark Gilbert, author of the Muscle Diet.
"This increases insulin, which is a fat-storage hormone, and causes rebound hunger and sluggishness once the excess sugar is cleared from the blood."
Tweaking the insulin response too regularly has also been blamed for the increase in late-onset diabetes, but a 2003 study at Kings College Hospital did show cereal breakfasts improved cognitive performance.
Nutrition scientist Nina Bailey also has a good word for cereals. "Protein curbs your appetite more than carbs, but you can get some by adding nuts to cereals that don't already have them."
A specialist in omega 3 - an essential fatty acid as vital as protein and fibre - she points out that seeds, nuts and eggs have some omega content - "though you would struggle to get enough without a supplement if you are not a fish eater. A kipper for breakfast would be a great source of omega 3 and protein."
One nutritionist who sees value in both protein-based breakfasts and a simple bowl of oats is Dr Marilyn Glenville, whose practice is in St Johns Wood, north-west London.
"Add protein to every meal", is one of her mantras - yet she also believes a bowl of porridge or a piece of whole-grain toast is better than nothing for working mothers in a hurry.
"Many people are so stressed rushing to get kids off to school and getting ready for work that they will just grab a cup of coffee," she says in her book, Fat Around the Middle.
"However, in doing so they are setting themselves up for failure… the blood sugar is raised, out pumps the excess insulin, giving the message loud and clear to store fat around the middle. If you miss breakfast, your body starts to attack the muscles, breaking them down for fuel. Blood sugar will drop, adrenaline and cortisol will kick in to try to correct the balance and you'll be looking for a quick fix."
She likes porridge because it provides a steady release of blood sugar. Oat-based muesli with nuts adds the protein quotient and needs no cooking.
The need for that other daily essential, vitamin C, is often met by a glass of calorific orange juice.
Israelis have a healthier approach, embracing fresh salads as well as protein-packed eggs, cheese and yoghurt in the morning, not to mention tahini. Tahini is rich in omega 3, vitamin B1, calcium, magnesium, manganese, phosphorous, iron, copper, zinc and some crucial amino acids.
Few of us have the time to do salads and tahini on a weekday, but my own version of an Israeli breakfast is rich in protein, calcium and vitamins and keeps me going for hours until lunch.
I simply chop a tomato and add copious amounts of fresh herbs (basil or coriander combined with chives) into half a cup or less of plain Greek yogurt, diluted with up to the same amount of cold water. Delicious - and not nearly as controversial as a bowl of cornflakes.