The study of time trends in household availability of all ultra-processed products in high-income Canada and upper-middle-income Brazil shows increases in both countries, at a faster rate in Brazil. It also shows that by the early 2000s, ultra-processed products had risen to over half of all calories consumed in Canada, and to over one-quarter in Brazil, from much lower levels. These findings are consistent with more recent changes in sales of selected ultra-processed products in 79 countries, also examined here. These show greatest consumption in high-income countries, but greater relative and sometimes absolute increases in lower-income countries. The data suggest that in high-income countries consumption of ready-to-consume snacks may remain static and that consumption of soft drinks may be past peak levels.
The findings of this study support previous analyses using Euromonitor data. These show fast-growing sales of ‘packaged foods’ (a reasonable proxy for ultra-processed products) in lower-income countries, and identify and forecast static sales in high-income countries [12, 23, 24]. Results from more recent food expenditure surveys conducted in Canada (2011) and Brazil (2008–2009) show no change in the share of ultra-processed products in Canada  and further increases in Brazil .
Previous and more detailed analyses of all foods purchased by households in Canada and Brazil show that ultra-processed products have displaced and are displacing staple foods, such as potatoes in Canada, and rice and beans in Brazil; and also other foods, such as legumes, milk, and fruits in Canada, and milk, cassava (manioc), vegetables and fruits in Brazil; and culinary ingredients in both countries [17, 18].
Displacement of foods and culinary ingredients by ultra-processed ready-to-consume products transforms food supplies and thus food culture and dietary patterns. The nature of ultra-processed products  indicates that these changes are harmful to public health. In general, ultra-processed products are more energy-dense and contain more harmful fats, and more sugars and salt, and less fibre, than unprocessed or minimally processed foods, as such, and also when combined with culinary ingredients such as oils, flours, sugars and salt into dishes and meals [17, 26]. Additionally, there is direct evidence of links between ultra-processed product consumption and overweight, obesity (Canella et al., unpublished data) and metabolic syndrome .
The scale of change in dietary patterns especially since the 1980s has been and still is so rapid, that some explanation is needed.
As societies become more urbanized, as available income grows and as the proportion of women employed outside the home increases, ready-to-eat and ready-to-heat food products become convenient and attractive choices. However, this alone does not explain the explosive recent increase in the consumption of ultra-processed products in lower- and upper-middle-income countries. The main reasons are economic as well as social.
Since the 1980s, national food systems have been shaped by dominant international economic policies designed to promote the flow of capital and the rapid expansion of trade. International and global trade agreements, intensified since the 1990s, have enabled transnational food manufacturing, retailing, ‘fast food’ chains and associated corporations, to become colossal [13, 28, 29].
The annual turnover of some transnational manufacturing corporations, collectively sometimes known as Big Food and Big Soda, and also Big Snack, is on a level with the gross national products of middle-size countries . They spend vast sums on advertising and marketing of their branded ready-to-consume products [13, 28, 29].
National and multinational supermarket chains, some owned by conglomerate corporations, have also rapidly increased in scale and reach, as have ‘fast food’ chains, at first in high-income countries and then globally [30-34]. Their profits also come largely or mainly from ultra-processed products. In the global South, the shift from small and specialist stores to supermarkets and smaller ‘mini-markets’ and ‘convenience stores’ first occurred in higher-income Latin America countries. Similar shifts also occurred in India and in other Asian countries such as Singapore, Hong Kong, South Korea and Taiwan, as available income increased . Thailand and China now both have a retail share of what is identified as ‘processed/packaged food’ of more than 60% . In lower-income countries and settings, food manufacturing transnationals also work through small retailers , and even by hiring door-to-door sellers of branded ‘popularly positioned products’ .
As the nature of what is consumed has changed, so have the ways of consumption. Food and culinary ingredients are mostly made into and consumed as meals, usually at regular times and normally in specified places. Ultra-processed products are mostly consumed as snacks, almost any time and anywhere. Up to the second half of the 20th century few adults consumed snacks. But now, in countries such as the United States, Canada, Mexico, Brazil and China, products in snack form amount to up to a quarter of all calories consumed [37-42]. In China, since 2000 snacking has tripled every 2 years . In lower-income countries, many snacks are currently in the form of fresh food such as fruits, but as income increases, more and then most are ultra-processed products, as in the United States [40-42]. It is suggested that the global strategy of transnational food manufacturing corporations is to ‘teach the world to snack’ on their branded products from infancy to old age .
The context and significance of what now amounts to a revolution in manufacture, distribution and sale, and thus in dietary patterns and the whole environment of eating and drinking, has been indicated by the director-general of the World Health Organization :
It is not just Big Tobacco anymore. Public health must also contend with Big Food, Big Soda, and Big Alcohol. All of these industries fear regulation, and protect themselves by using the same tactics … These … include front groups, lobbies, promises of self-regulation, lawsuits, and industry-funded research that confuse the evidence and keep the public in doubt. … This is formidable opposition. Market power readily translates into political power. Few governments prioritize health over big business. As we learned from experience with the tobacco industry, a powerful corporation can sell the public just about anything.