The breakfast mistake you didn't realise you were making.

Breakfast: Your first chance to start the day right – so why are so many of us getting it wrong?

Cereal has become as common to the breakfast table as the wood itself but according to nutritionists, it may be one of the worst ways to start your day.

High in carbohydrates and often hiding added sugars, it’s no wonder you’ve scheduled that 10am snack break.

"Many commercial breakfast cereals, including those that claim to be healthy, are very high in added sugars," nutritionist Kristen Beck told news.com.au.

Beck explained that many cereals are "concentrated sources of sugar" that possess it in the forms of honey or dried fruit.

Muesli was also on the naughty list with its additions of fruit and sweeteners in the forms of honey, malt and molasses.

"Toasted muesli's also contain significant amounts of fat."  Beck said.

The biggest bad behind the box seems to be sugar as it offers little health benefit and can lead to long-term conditions such as heart disease and type two diabetes.

So if cereal and muesli are a no-go, what foods should we be eating between our bed and the bus?

According to the Australian Government's Better Health resource, ideal breakfast options are full of fibre or proteins such as dairy.

A serve of yoghurt and fruit or some protein-rich eggs may be the saviour to your mid-morning munchies.

If parting with your morning bowl is too big an ask, try filling it with something more wholesome and lower in added sugar or fat.

Better Health recommends a bowl of rolled oats with some low-fat milk and a few sultanas for that sweeter hit.

And if breakfast is something you regularly skip, you might want to tempt yourself, as studies show adults who eat breakfast are more likely to perform better at work and maintain a healthy weight.

Listen to a nutritionist explain what happens to your body when you skip that first meal of the day.