Taste preferences and brand loyalty are established during infancy, so the industry pushes highly processed foods and sweetened drinks on children from a young age.
According to the articles, only 1 in 4 countries have been implementing a policy on healthy eating up to 2010.
The Lancet series notes that although rates of child obesity have started to level off in certain cities and countries, no country to date has seen declining rates of obesity on a population-wide level.
Children in the US, for example, weigh an average of 5 kg more than they did 30 years ago, with 1 in 3 children being overweight or obese.
In new estimates produced for the series, The Lancet reports that American children are consuming an average of 200 kcal more per day than they were in the 1970s. This extra consumption works out as an extra $400-worth of food being consumed per child per year, adding up to an extra $20 billion in annual sales for the US food industry.
Put simply? "Fat children are an investment in future sales." This is the opinion of Dr. Tim Lobstein from the World Obesity Federation, co-author of the series, who also calls for an integrated approach in tackling both overnutrition and undernutrition.
"Undernutrition and overnutrition have many common drivers and solutions, so we need to see an integrated nutrition policy that tackles both these issues together to promote healthy growth for children," says Dr. Lobstein.
More than a fifth of children under 5 years of age are affected by stunting in low- and middle-income countries, but rapidly rising levels of obesity in these same countries can also pose a threat to these populations. As an example of how these combined problems might affect individuals, the authors explain that poorly nourished infants may not develop their full height but still gain more than their full weight.
As such, the report emphasizes the importance of ensuring that the supply of food encouraging healthy growth is not jeopardized by the food industry's aggressive marketing of cheap, less nutritious products.
The food industry, the authors remind, has a special industry in targeting children. Taste preferences and brand loyalty are established during infancy, so the industry pushes highly processed foods and sweetened drinks on children from a young age.
Illustrating this point, the authors report that the global market for processed infant foods is expected to be worth $19 billion in 2015, up from $13.7 billion in 2007.
Governments rely on food industry's voluntary initiatives, rather than proposing solutions
Countries are not taking necessary steps to protect children from obesity, the report finds, with both regulation and healthy food policies lacking. Instead, most countries rely on the food industry's own voluntary initiatives, and there is no evidence for these programs' effectiveness.
"It's time to realize that this vicious cycle of supply and demand for unhealthy foods can be broken with 'smart food policies' by governments alongside joint efforts from industry and civil society to create healthier food systems," says Dr. Christina Roberto, from the Harvard T.H. Chan School of Public Health in Boston, MA.
Among the recommendations set out in the series are a call for civic action to combat obesity - similar to the pressure from the public that saw universal health care access granted to HIV/AIDS patients in South Africa - and that more must be done to improve the training of health care professionals.
Part of this training should be to counter biases about patients with obesity and improve delivery strategies for care, say the authors.
Series lead author, Prof. Boyd Swinburn from the University of Auckland, New Zealand, summarizes the recommendations:
"The key to meeting WHO's target to achieve no further increase in obesity rates by 2025 will be strengthening accountability systems to support government leadership, constraining the role of the food industry in the formation of public policy, and encouraging civil society to create a demand for healthy food environments."