Sticking to official dietary advice, including the five-a-day maxim, could reduce the chance of premature death by an estimated 7% as well as help the environment, a study has suggested.

However, it found that while many people are able to follow some of the guidelines, next to no one follows them all.

The first analysis of nine government-backed Eatwell dietary guidelines found that those who adhered to five or more of them had an estimated 7% reduction in their mortality risk.

The research, led by the London School of Hygiene & Tropical Medicine, in collaboration with the University of Oxford, suggested a similar diet was associated with a 30% reduction in carbon dioxide emissions, compared with those that adhered to two or fewer.

“Our study demonstrates that the Eatwell Guide forms an effective first step towards more healthy and sustainable diets in the UK,” said Dr Pauline Scheelbeek, assistant professor in nutritional and environmental epidemiology at the London School of Hygiene & Tropical Medicine (LSHTM) and the study’s lead author.

“Further adherence to the guidelines would not only result in population health benefits, but is also associated with lower environmental footprint due to reduced greenhouse gas emission.”

Prof Alan Dangour, the study’s senior author, added: “Our new analysis demonstrates that following the Eatwell Guide would substantially improve human health in the UK and reduce our nation’s footprint on the planet.”

The guidelines, which were published in 2016, recommend that people eat at least five portions of a variety of fruit and vegetables per day, as well as base meals of potatoes, bread, rice, pasta or other starchy carbohydrates and drink six to eight glasses of fluids per day.

The advice also calls for diets to include dairy and sources of protein, such as beans and oily fish, and for people to choose unsaturated oils and spreads and eat fewer foods high in fat.

Recommended low-calorie snacks that would adhere to the guidelines include a cheese and tomato toastie using crispbread, baked beans on toast and homemade popcorn.

The researchers found that the most marked improvement in mortality risk – when adhered to alone – was the consumption of fruit and vegetables. That reduced the estimated risk by 10%, they said in the study, which appears in BMJ Open and was funded by the Wellcome Trust.

Despite the benefits, data from the National Diet and Nutrition Survey suggest that less than 0.1% of the population is able to adhere to all nine guidelines. The data showed that 44% of people are able to follow three or four of the recommendations, with the consumption of dietary fibre and oily fish being the least commonly met category.

One of the most important environmental factors is the consumption of red or processed meat, which contributes to greenhouse gas emissions. The authors said their study indicated that limiting that and eating more beans, pulses and sustainably sourced fish instead would have a significant impact.

However, Scheelbeek said that “more transformational dietary shifts than those recommended in the Eatwell Guide will be necessary if we want to meet the Paris agreement targets”.

She said: “The Eatwell Guide does not specifically target environmental sustainability of diets. We therefore need to investigate ways to further reduce environmental footprints of our diets in ways that would be culturally acceptable and could be implemented by the UK population, both from a consumption and a production side, without compromising population health.”