Why the color of the food we eat is important

Most of us are faced with the same choice numerous times a day: what to eat. Along with price, accessibility and preference, we'll often use a food's healthfulness to help us make a decision.

But when we zoom out to inspect our overall diets, how do we know we're getting the nutrients we need?

It's widely accepted by researchers that we need a varied diet, and that one way to do this is by eating all the colours of the rainbow. But is colour the best guide to getting all the nutrients we need?

The proof may be in the Mediterranean diet, which contains a lot of fruit, vegetables and healthy fats such as extra virgin olive oil, and is frequently rated the healthiest diet by scientists.

It's no coincidence that the diet is packed with different colours, says Francesco Sofi, associate professor of clinical nutrition at the University of Florence.

"Eating a traditional Mediterranean diet means you consume different nutrients and phytonutrients," he says. Phytonutrients are small chemical compounds produced by plants that help us to digest larger nutrients and also play a role in removing toxins from our bodies.

"However, the diet doesn't always contain every colour – it depends on the season, as followers of the diet eat seasonally and locally, and grow their own fruit and vegetables."

Really, he adds, the colours are no different to other vegetable-based diets, such as the vegetarian diet. There are also other reasons the Mediterranean diet is among the healthiest. Mediterranean populations traditionally boil, rather than fry, their vegetables, which preserves nutrients, Sofi says.