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Unhealthy diets rise across majority of countries worldwide

Overall consumption of unhealthy foods around the world has increased, despite an improvement in healthy food consumption, according to a recently published study in The Lancet Global Health.

“Poor diet quality is now the number one cause of poor health in the U.S. and the world, causing enormous suffering and costing trillions of dollars,” Dariush Mozaffarian, MD, DrPH, of the Friedman School of Nutrition Science and Policy at Tufts University, said in a press release.

Mozaffarian and colleagues performed a systematic assessment of 325 surveys, conducted in 1990 and 2010, which encompassed over 88% of the world’s adult population, to assess global dietary trends. Researchers divided the mean intakes of each dietary factor into quintiles, and each received an ordinal score from 0 to 100; higher scores meant healthier diets.

Evaluated healthy foods included fruits, vegetables, beans and legumes, nuts and seeds, whole grains, milk, total polyunsaturated fatty acids, fish, plant omega-3s, and dietary fiber, while unhealthy foods consisted of unprocessed red meat, processed meats, sugar-sweetened beverages, saturated fat, trans fat, dietary cholesterol, and sodium.

Disparities across nations

Global consumption of healthy foods increased overall from 1990 to 2010 by 2.2 points (95% uncertainty interval (UI), 0.9-3.5), but unhealthy diets also worsened (– 2.5 points; 95% UI, – 3.3 to – 1.7). Results demonstrated that generally, older adults and women had better diets compared to younger adults and men (P < 0.0001).

The researchers saw a strong association between a country’s national income and diet quality. Nations with high-incomes were linked to healthier diets in comparison with lower income countries (+ 2.5; 95% UI, 0.3-4.1), but they also had have significantly lower unhealthy diet scores (– 33; 95% UI, –37.8 to – 28.3). An association between unhealthy diets and income was also seen in upper middle-income countries (95% UI, – 30.2 to – 20.2) and lower middle-income (95% UI, – 23.7 to – 13.2) countries compared to low-income countries.  

“In some countries, lack of healthy foods is the biggest problem; in others, excess unhealthy foods; and in others, such as the United States, it's both. This tells us there is no one-size-fits-all approach to improving global diets,” Mozaffarian said in the press release.

Notably, no increase in healthy foods were seen in the world’s poorest areas, such as sub-Saharan Africa and the Andean states of Latin America. “The lack of improvement [in these regions] underlines the urgent need to address diet quality in the poorest nations, where rises in obesity, diabetes and cardiovascular diseases are joining undernutrition and nutrient deficiencies as health problems,” Fumiaki Imamura, PhD, of the MRC Epidemiology Unit at University of Cambridge School of Clinical Medicine in the United Kingdom, said in a press release.

“These new findings can be used to inform policies and prevention efforts aimed at improving dietary patterns to reduce burdens,” Mozaffarian said in the release.

In an accompanying editorial, Carlo La Vecchia, MD, of the department of clinical sciences and community health at Università degli Studi di Milano, Italy, notes that while the study gives important insights into dietary trends, it does not take into account differences in dietary components between countries vs. the items included in the study. For instances, diets in higher income countries are more homogeneous while diets in middle or lower income countries may be more heterogeneous.

“The highest scores for healthy foods are in several low-income countries, as well as a few Mediterranean ones, reflecting favorable aspects of the Mediterranean diet,” La Vecchia wrote. “In view of the importance of diet and nutrition on health and related societal issues, the key focus of the paper remains the need to understand the agricultural, trade, and food industry, and health policy determinants to improve dietary patterns and nutrition in various areas, taking into account the traditional characteristics of diets worldwide.” – by Casey Hower

Disclosure: Imamura reports no relevant financial disclosures. La Vecchia reports receiving a consulting fee from Ferrero. Please see the full study for a list of all other authors’ relevant financial disclosures.