Should you start your day strong with breakfast or wait it out for a better lunch? Here’s what happens to your body when you miss breakfast:

Ever heard the phrase "go to work on an egg"? Still occasionally bandied around today, this was actually a slogan dreamt up by the UK Egg Marketing Board in the 1950s.

Far from being based on science or nutrition, it was simply a marketing effort to encourage people to eat more eggs – but had the effect of making many believe that breakfast was key.

Similar concepts, such as breakfast being the "most important meal of the day," are commonplace, but is this notion actually true?

And on the flip side, what does science say about skipping breakfast? Is it effective as a weight-loss method, for example, or does it have health implications?

Is it OK to skip breakfast?

These days, skipping breakfast is commonplace. The rise in popularity of intermittent fasting has seen many people foregoing their morning meal in the hope of losing a few pounds.

According to a survey, 13 percent of adults never eat breakfast.

Others, however, swear by their morning meal, and you only have to look at the rising popularity of shakes, smoothies, and nut and seed toppings for bowls of yogurt or overnight oats to see how big the market for breakfast actually is.

Some specialist dietitians say having a meal at some point in the morning is important, but it is a personal preference what time this takes place.

The name literally means "breakfast." What the meal contains, rather than the timing, is more important. Some people might prefer a later, more substantial breakfast, while others want to eat immediately when they wake up.

What happens when you skip breakfast?

For some people, missing breakfast is no big deal. They simply don't feel hungry first thing, and it can help them get up and out quicker in the mornings.

But if you’re used to starting the day with some food and a cuppa, going without can feel odd. Not only is it part of your morning routine, but your body is used to being refuelled, so chances are you’ll probably feel hungry and a bit light-headed without it.

Inside your body, a lot is going on. Intermittent fasting can cause changes in your body’s hormone levels.

It can decrease insulin levels and improve insulin sensitivity, which is beneficial for weight loss overall and reduces your risk of diabetes.

But one study found that skipping breakfast and late meal consumption decreased the hormone leptin (which helps you feel full) while increasing the hunger hormone ghrelin.

Cutting out breakfast can also raise your levels of the stress hormone cortisol. What’s more, it significantly raises your levels of 'bad' LDL cholesterol, according to various studies, and those who skip breakfast are 21 percent more likely to experience cardiovascular disease.

The impact is not the same for everyone, but skipping breakfast can lead to low energy levels and impaired cognitive function, or brain fog.

This is due to low blood sugar, as the body does not have a ready source of energy. Glycogen, which is stored around the liver and in muscles, sustains us during periods of fasting overnight.

However, it is generally depleted by the morning, and the body has to use its own tissues to provide energy, which is less efficient. The brain needs a constant source of carbohydrate to function at its peak.

Is skipping breakfast good for weight loss?

It depends on which studies you read, but yes, apparently so. According to a recent scientific review, people who went without breakfast lost an average of 0.66 kg of weight compared with those who didn’t.

And other studies show that those who eat breakfast consume around 260 calories more per day than those who don’t.

However, it can also disrupt your metabolism and your gut microbiome, the ecosystem of microbes that live in your intestines.

Missing breakfast does not necessarily mean you will consume fewer calories or that the rest of your meals will be balanced and provide all the nutrients you need.

It can lead to snacking due to increased hunger. A better plan is to eat intuitively, listening to your hunger cues and eating when you are hungry, whatever time that is.

So, while skipping breakfast is on-trend, there are plenty of reasons why you should stick with your brekkie