An ideal diet would be both healthy for the individual and sustainable for the planet, but according to an international team of researchers, we are falling short of that goal around the world.
A report published in The Lancet on Jan. 16 of this year highlighted both the dangers of current global food systems and provided suggestions, including an ideal “reference diet,” that would serve to guide improvements. The authors of the study were from 16 countries, and their expertise spanned topics from agriculture to political science.
The report began by noting that although advances in technology and crop yields have led to a reduction of hunger and have had a positive effect on human health over the past half-century, the recent shift toward high-calorie, highly-processed food is eroding gains. A significant number of people, more than 820 million globally, remain undernourished, while at the same time the incidence of obesity and related non-communicable diseases is increasing.
Current diets are also environmentally unsustainable. Food production takes up a significant percentage of global land, accounts for nearly 70 percent of freshwater use and is a major contributor to habitat destruction.
The authors first focused on the issue of health by creating a reference diet, drawing information from controlled feeding studies, reviews and meta-analyses. They decided on a diet consisting of 2500 kilocalories (kcal) per individual per day, slightly higher than the current average of 2370 kcal per day.
Consumption of red meat, which evidence has suggested is both nonessential and associated with higher risk of negative health outcomes, was recommended to be between zero grams (g)/day to 28 g/day, with 14 g/day chosen for the reference diet. Poultry, dairy and fish were recommended in higher amounts, and nuts and legumes were included as further sources of protein. The authors also recommended high intake of fruits and non-starchy vegetables — 500 g/day in total — and the use of unsaturated plant oils in moderate amounts.
The authors evaluated their reference diet for its benefits by looking at nutritional value and effect on mortality rates. Aside from being more nutritionally adequate when compared to current typical diets in various regions of the world, the analysis indicated that the reference diet could prevent over ten million deaths per year from diseases such as coronary heart disease and type II diabetes.
Sustainability was also addressed by the researchers, with major environmental issues including biodiversity loss, greenhouse gas emissions, freshwater use, and nitrogen and phosphorus use.
The authors stated that the proposed reference diet has the potential to reduce negative impacts through its higher fruit and vegetable and lower meat recommendations, since studies have indicated the smaller environmental impact of plant-based foods.
Dietary changes, however, were not the only suggested improvements. The researchers also recommended updating irrigation and fertilization systems, planting higher-yield crops, reducing food waste, and creating more protected areas in order to preserve existing habitats and their biodiversity.
Any transformation of food systems will differ based on local contexts. The researchers noted that differing climates and soil conditions in various parts of the world will affect what changes can be made to agriculture. Presently, regions also differ in their diets, and as a result the alterations necessary to approach the reference diet vary.
However, the authors cautioned that all efforts should be made toward a set of common goals and that frequent communication and interaction is important. They acknowledged that attempting the suggested changes will be a huge undertaking, involving partnerships between the government, private sector and citizens; scientific research; and continuous policy adjustments.
Although the task is formidable, the researchers emphasized that the issues discussed in the report are time-sensitive and will rapidly worsen if unaddressed. They were, however, optimistic about the possibility for change, especially if partnerships and collaborations are formed globally.