PHD Diet Lowers Risk of Death and Saves the Planet

The Planetary Health Diet reduces the risk of several chronic conditions and protects the environment.

Livestock is responsible for about 11% of all human-derived greenhouse gas emissions, making it one of the major drivers of climate change.

In 2019, the report from the Lancet Commission on Healthy Diets from Sustainable Food Systems emphasized the need for a healthy diet that would also help improve sustainable food systems, minimizing damage to the planet.

The commission defined a Planetary Health Diet (PHD), which focuses on a variety of minimally processed plant foods while allowing modest consumption of meat and dairy.

A new study published in the American Journal of Clinical Nutrition examined the impacts of adherence to the Lancet report recommendations.

The researchers used health data from more than 200,000 health professionals. At the beginning of the study, the participants were free of cancer, diabetes, and major cardiovascular diseases. They completed dietary questionnaires every four years for up to 34 years.

To quantify participants’ adherence to the PHD, the researchers evaluated their diets based on intake of 15 food groups, such as whole grains, vegetables, poultry, and nuts.

In women but not men, the PHD diet was also significantly associated with a lower risk of death from infectious diseases.

Additionally, the highest adherence to the PHD substantially reduced environmental impact compared to the lowest adherence, including 29% lower greenhouse gas emissions, 21% lower fertilizer needs, and 51% lower cropland use.

The researchers say that land use reduction facilitates reforestation, which is seen as an effective way to further reduce the levels of greenhouse gases driving climate change.

Lauryna Nelkine, MSc in nutrition science and a managing health content researcher at Healthnews, says the PHD diet is one of the ways to tackle the current climate crisis by adjusting our eating habits and improving our health.

Although the study findings are promising, Nelkine emphasizes that observational studies like this establish associations rather than causation between certain diets and long-term health outcomes.

Even though a nutritionally balanced diet is a major contributor to our health and longevity, many other factors besides our diet could impact the risk of developing certain diseases.

Nelkine

Moreover, the method of measuring adherence to the diet using self-reported food frequency questionnaires is prone to bias since participants tend to forget to include certain socially undesirable foods or report eating more of certain health-promoting foods.

“People tend to forget what they ate yesterday, so reporting what and how much you ate in the last month or quarter could be especially problematic,” Nelkine says.

What is the PHD diet?

Approximately half of a Planetary Health Diet plate should consist of vegetables and fruits, while the other half should focus on whole grains, plant protein sources, and unsaturated plant oils, such as olive and avocado oils.

Some examples of plant-based proteins include lentils, quinoa, tofu, beans, and chickpeas.

Modest amounts of animal protein sources, such as eggs, poultry, and dairy products, are optional in this eating pattern.

In the Planetary Health Diet, the intake of refined grains, highly processed foods, added sugars, and red meat should be limited.

The Lancet Commission suggests that the average adult should consume 2,500 kcal per day. While this amount may vary based on age, gender, activity levels, and health profiles, overconsumption is a waste of food that negatively impacts health and the environment.

According to Nelkine, the PHD diet may not be suitable for all individuals, especially because it limits animal-based foods, which are rich in certain micronutrients. By abstaining from animal-based foods, deficiencies may occur in vulnerable population groups, or during specific life stages, like pregnancy.