Dietary fats, human nutrition and the environment: balance and sustainability

April 25, 2022

A new study by Wageningen University & Research and Charles University in Prague considers both nutritional and environmental consequences so as to shine a novel light on dietary oils and fats. Rather than considering all such fats as simply bad for our health, it highlights the importance of fats in healthy diets, especially among undernourished people, and the need for making wise choices among vegetable and animal sources of fat regarding planetary and human health.

To choose the right sources of oils and fats involves a complex balance of nuanced and changing issues. Although recent studies indicate that saturated fats from animals are not as unhealthy as often claimed, the environmental impacts of animal fats from dairy, lard, tallow, and other sources tend to be much greater than those from plants. But even among plant fats our choices have major implications. Palm oil, coconut oil and peanut oil are important affordable oils in parts in the world with the greatest “fat gaps” – the difference between how much we consume and should consume in a healthy diet. But the flipside is that the expansion of the crops have been seen to negatively impact tropical forests and biodiversity. Most soybean, rapeseed and sunflower are grown in wealthier and more temperate parts of the world, and are associated with excessive nitrogen flows and some significant land system changes, such as the expansion of soy into South American forest and savannas.

The study published in Frontiers in Nutrition is highly topical with the Ukraine war and its impact on Russian and Ukrainian sunflower oil production having sparked major price increases for vegetable oils. The new study provides a framework for predicting what the implications could be of changes in oil production and trade on poor and undernourished people and the global environment.

Douglas Sheil, senior author and a Professor at Wageningen University & Research, said: “In our search for good foods I see again and again that we are overly keen to accept simple answers such as the idea that dietary fats are harmful and that avoiding palm oil saves forests. Constructive answers require a more nuanced reflection on the specific implications of the specific commodity in a specific context. Fats are essential to health, and any source of food oils can be good or bad. What I found particularly striking in our study, is how any efforts to guide and improve the nature of the required production so as to achieve better health and environmental outcomes remains undermined by inadequate information. This while global demand for dietary oils and fats are likely to double over the next three decades.”

Professor Erik Meijaard, the study’s lead author and Visiting Professor at Charles University, said: ”In the heated debates about oils and fats, where many argue that fats should just be excluded from diets, we forget that, as humans, we really are “fat hunters”. About 25–30% of our daily energy needs come from fats, and without fats, we die. It therefore becomes important where we source our fats – from animals or plants, and which animals and plants, and what the impacts are of our choices.”

The study highlights that any simple conclusions about oils and fats are likely to miss the picture. Saturated fats are not necessarily unhealthy. Palm oil is not necessarily bad. Wise choices about the production, trade and consumption need to be made in the broader context of how different oils and fats affect the health of both overweight and undernourished people and the health of the planet.