The food industry has infiltrated the World Health Organisation, just as the tobacco industry did, and succeeded in exerting "undue influence" over policies intended to safeguard public health by limiting the amount of fat, sugar and salt we consume, according to a confidential report obtained by the Guardian.

The report, by an independent consultant to the WHO, finds that:

· food companies attempted to place scientists favourable to their views on WHO and Food and Agricultural Organisation (FAO) committees

· they financially supported non-governmental organisations which were invited to formal discussions on key issues with the UN agencies

· they financed research and policy groups that supported their views

· they financed individuals who would promote "anti-regulation ideology" to the public, for instance in newspaper articles.

"The easy movement of experts - toxicologists in particular - between private firms, universities, tobacco and food industries and international agencies creates the conditions for conflict of interest," says the report by Norbert Hirschhorn, a Connecticut-based public health academic who searched archives set up during litigation in the US for references to food companies owned or linked to the tobacco industry.

He finds that there is reasonable suspicion that undue influence was exerted "on specific WHO/FAO food policies dealing with dietary guidelines, pesticide use, additives, trans-fatty acids and sugar.

"The food industry is considerably engaged in genetically modified foods and the tobacco industry has studied the matter closely with respect to its product; there is evidence the tobacco industry planned also to influence the debate over biotechnology."

The WHO and FAO need the scientific input of the food industry, says the report, but that input must be transparent and subject to open debate.

"One industry-led organisation, International Life Sciences Institute (ILSI), has positioned its experts and expertise across the whole spectrum of food and tobacco policies: at conferences, on FAO/WHO food policy committees and within WHO, and with monographs, journals and technical briefs."

Some of the strongest criticism in the report is levelled against the ILSI, founded in Washington in 1978 by the Heinz Foundation, Coca-Cola, Pepsi-Cola, General Foods, Kraft (owned by Philip Morris) and Procter & Gamble. Until 1991 it was led by Alex Malaspina, vice-president of Coca-Cola.

Dr Malaspina established ILSI as a non-governmental organisation "in official relations" with the WHO and secured it "specialised consultative status" with the FAO.

Eileen Kennedy, global executive director of ILSI, said that the funding of its regional groups came exclusively from industry, while the central body received money from the branches, from government and from an endowment set up by Dr Malaspina. Nonetheless, she said, ILSI regarded itself as an independent body.