Eating a handful of nuts could give you an extra 25 minutes of ‘healthy life’ every day, according to a study just published in the journal Nature Food (1).

About the research

Researchers from the University of Michigan developed a world-first ‘Health Nutritional Index’ (HENI).

They used this to assess whether 5,853 individual foods, consumed in the US diet, either added or took minutes away from a ‘healthy life’ – that is, an increase in good-quality and disease-free life expectancy.

Using the Global Burden of Disease study (2), the index analysed 15 dietary risk factors to estimate the effect of a particular food. The scientists also took the food’s environmental impact into account, including its carbon footprint and water use.

Finally, the different foods were grouped according to a traffic light system – colour-coded as either green, yellow or red.

Green, amber and red zone foods

The ‘green zone’ was made up of foods that boost health and have little environmental impact, like nuts, fruit, ‘field-grown’ vegetables, legumes, whole grains and certain seafood.

In contrast, the ‘red zone’ included meat – whether red or processed, prawns and ‘greenhouse-grown’ vegetables. ‘Amber zone’ foods included dairy foods, poultry and egg-based foods.

Small targeted changes, such as eating a handful of nuts daily, are a ‘do-able’ and powerful way to gain health and environmental benefits.

Key findings

  • Substituting just 10% of daily calorie intake from beef or processed meat in favour of fruit, vegetables, nuts, legumes and ‘selected seafood’ adds 48 minutes of healthy life every day and cuts our carbon footprint by a third (33%).
  • Eating a 30g serve of nuts and seeds provides a gain of 25 minutes of healthy life per day.
  • Eliminating processed meat and reducing overall sodium consumption provides the largest gain in healthy life compared with all other food types.

Table: Health nutrition index of certain foods (1)

Food Minutes
(median gained (+) or
lost (-) of healthy life)
Nuts & seeds + 25 mins
Legumes & soy products + 10 mins
Fruits + 12 mins
Seafood + 5 mins
Vegetables (non-starchy varieties) + 2 mins
Red meat – 6 mins
Pizza – 6 mins
Sweetened beverages – 8 mins
Processed meat (‘cured meat/poultry’) – 26 mins
Hot dog (‘frankfurter sandwich’) – 36 mins

Eating a 30g serve of nuts and seeds provides a gain of 25 minutes of healthy life.

Plant-based versus animal-based

Previous studies investigating healthy or sustainable diets have tended to compare plant- and animal-based foods.

But according to the University of Michigan researchers, this can be overly simplistic, given the wide variations of foods within the broad ‘plant-based’ and ‘animal-based’ food categories.

They say HENI scores translate complex nutrition information into a simple but meaningful score for individual foods – through minutes of healthy life gained or lost – and, taken together with a food’s environmental impact, allows specific foods to be compared.

The researchers suggest their work should inform future dietary guidelines, to maximise health benefits while reducing environmental impacts.

The bottom line

The researchers hope their work inspires and empowers a transition towards healthy and environmentally sustainable diets, changing one food at a time.

They suggest reducing the most impactful ‘red zone’ foods first, and prioritising the most nutritionally-beneficial foods – including nuts, legumes, field-grown fruit and vegetables, and low-environmental impact seafood. And this should be done hand-in-hand with a diverse, varied diet.

To sum up, they say: “Our findings demonstrate that small, targeted substitutions offer a feasible and powerful strategy to achieve significant health and environmental benefits, without requiring dramatic dietary shifts”.

This is in line with the landmark EAT-Lancet Commission on Food, Planet and Health, which supports small changes for a large and positive impact (3).

According to the EAT-Lancet Commission on Food, Planet and Health, global intake of nuts needs to double from current levels. 

References

  1. Stylianou, KS., Fulgoni, VL., Jolliet, O. Small targeted dietary changes can yield substantial gains for human and environmental health. Nature Food, 2021. 2:616–27.
  2. Gakidou, E., et al. Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet 2017. 390:1345–1422.
  3. Willett, W. et al. Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems. Lancet, 2019. 393:447–92.
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