The findings are from the EAT-Lancet Commission which provides the first scientific targets for a healthy diet from a sustainable food production system that operates within planetary boundaries.
Current diets are pushing the earth beyond its planetary boundaries, while causing ill health.
This puts both people and the planet at risk.
The 32-page report, made public on Thursday, promotes diets consisting of a variety of plant-based foods, with low amounts of animal-based foods, refined grains, highly processed foods and added sugars and unsaturated rather than saturated fats.
Human diets inextricably link health and environmental sustainability and have the potential to nurture both.
Providing healthy diets from sustainable food systems is an immediate challenge as the population continues to grow - projected to reach 10 billion people by 2050 --and get wealthier with the expectation of higher consumption of animal-based foods.
To meet this challenge, dietary changes must be combined with improved food production and reduced food waste.
The authors of the report stress that unprecedented global collaboration and commitment will be needed, alongside immediate changes such as refocussing agriculture to produce varied nutrient-rich crops, and increased governance of land and ocean use.
"The food we eat and how we produce it determines the health of people and the planet, and we are currently getting this seriously wrong," says one of the commission authors Tim Lang of City, University of London.
"We need a significant overhaul, changing the global food system on a scale not seen before in ways appropriate to each country's circumstances. The scientific targets we have devised for a healthy, sustainable diet are an important foundation which will underpin and drive this change."
The Commission is a three-year project that brings together 37 experts from 16 countries with expertise in health, nutrition, environmental sustainability, food systems, economics and political governance.
What are the scientific targets for a healthy diet?
Despite increased food production contributing to improved life expectancy and reduction in hunger, infant and child mortality rates and global poverty over the past 50 years, these benefits are now being offset by global shifts towards unhealthy diets high in calories, sugar, refined starches and animal-based foods and low in fruits, vegetables, whole grains, legumes, nuts and seeds and fish.
The authors argue that the lack of scientific targets for a healthy diet have hindered efforts to transform the food system.
Compared with current diets, global adoption of the new recommendations by 2050 will require consumption of foods such as red meat and sugar to decrease by more than 50 per cent, while consumption of nuts, fruits, vegetables, and legumes must increase more than two-fold.
Global targets will need to be applied locally. For example, countries in North America eat almost 6.5 times the recommended amount of red meat, while countries in South Asia eat only half the recommended amount.
All countries are eating more starchy vegetables (potatoes and cassava) than recommended with intakes ranging from between 1.5 times above the recommendation in South Asia and by 7.5 times in Sub-Saharan Africa.
"The world's diets must change dramatically. More than 800 million people have insufficient food, while many more consume an unhealthy diet that contributes to premature death and disease," says co-lead Commissioner Walter Willett of Harvard University.