Although our planet is covered in water, the freshwater portion humanity can use for its purposes is exceedingly small - and we need to make sure we don't waste this essential resource.

A new study from researchers at the Directorate for Sustainable Resources in Italy has investigated how diet impacts our individual water footprints, and for once, it's good news! If you want to save water, just eat healthier.

According to the latest research, you can lower your food water footprint by up to 35 percent simply by making your diet healthier, which includes limiting meat, although not necessarily cutting it out altogether.

However, if you do opt for a healthy pescetarian or vegetarian diet, this effort could limit your food water footprint by up to 55 percent.

The researchers first investigated the different average food water footprints for the UK, France and Germany using census information, known water footprint of individual food and drinks, and knowledge of local eating habits to understand how much water is being used to feed people.

On average, the UK looked to have the smallest food water footprint at 2,757 litres per person per day. Germany was 2,929 litres per day, and France was 3,861 litres per day.

If that seems like a lot, you're not alone. And it's important to note this isn't even the whole water footprint – it doesn't include any water you would use at home, or water used for non-food items you would buy at the shops. (It can take 2,700 litres just to produce the cotton for one t-shirt.)

"If you look at the numbers for the countries it goes to 3,000 - 4,000 litres per person per day; these are enormous amounts when you compare them with direct water use at home," one of the team, agricultural scientist Davy Vanham explained to the BBC.

But if people shifted their diets to the national healthy dietary guidelines of the three countries, the water footprint related to their food alone would be reduced by a significant amount.

However, how much water you save does depend on where you live, and is also affected by choices such as how much wine you drink versus beer, or how much extra sugar, oil, or dairy products you consume.

"The main message is that if you shift to a healthy diet, be it with meat or without (vegetarian or pescetarian), according to your own preference, it's not only good for your health, but it's also very good for the environment in the sense that you reduce your water footprint substantially," Vanham added.

The researchers aren't advocating for this as the only solution, but it can be an easy win-win for those people who want to do their bit, and eat healthier in the process. Apart from food choices, there are many ways to lower your footprint - you can find out your entire water footprint (if you're in the US) here.

This study does show that small contributions can still have a major effect. And with water scarcity affecting over 2.7 billion people for at least one month each year, it's important we do what we can to lower our water footprint, as well as our carbon one.

The research was published in Nature Sustainability.