Breakfast is the most important meal of the day. Picture: Instagram (thedishonhealthy)

They say breakfast is the most important meal of the day and one Harvard physician says there's a fail-safe three-ingredient breakfast everyone should have every single day.

Monique Tello revealed that having a bowl of cereal, a bagel or a piece of toast first thing is no different to having dessert for breakfast.

Instead, she opts for an Icelandic-esque breakfast of three nutrient-dense ingredients: berries, high protein yogurt, and oats.

Tello says this meal is perfect to kick off the day because it's packed with two key ingredients: protein and fibre.

These nourishing ingredients fuel our muscles, keep us full and regulate digestion.

Tello says she always uses frozen berries because the vitamin content is higher but cheaper and lasts longer.

Explaining her choice, she said that berries are packed with fibre, as well as Vitamins A, C, and K.

As for her choice of yoghurt, she loves plain yoghurt, a brand of high-protein, low-sugar yogurt from Iceland. 

She recommends plumping for a plain Greek yogurt with less sugar. On top of the mix, she will sprinkle either oats or nuts and seeds. 

She always opts for unsalted nuts, toasted pepita seeds, and whole rolled oats because they're high in fibre and protein.