<P> Testing on rats has indicated negative effects of junk food that may manifest likewise in people . A Scripps Research Institute study in 2008 suggested that junk food consumption alters brain activity in a manner similar to addictive drugs like cocaine and heroin . After many weeks with unlimited access to junk food, the pleasure centers of rat brains became desensitized, requiring more food for pleasure; after the junk food was taken away and replaced with a healthy diet, the rats starved for two weeks instead of eating nutritious fare . A 2007 study in the British Journal of Nutrition found that female rats who eat junk food during pregnancy increased the likelihood of unhealthy eating habits in their offspring . </P> <P> Other research has been done on the impact of sugary foods on emotional health in humans, and has suggested that consumption of junk food can negatively impact energy levels and emotional well - being . </P> <P> In a study published in the European Journal of Clinical Nutrition, the frequency of consumption of 57 foods / drinks of 4000 children at the age of four and a half were collected by maternal report . At age seven, the 4000 children were given the Strengths and Difficulties Questionnaire (SDQ), with five scales: hyperactivity, conduct problems, peer problems, emotional symptoms and pro-social behavior . A one standard deviation increase in junk food was then linked to excessive hyperactivity in 33% of the subjects, leading to the conclusion that children consuming excess junk food at the age of seven are more likely to be in the top third of the hyperactivity scale . There was no significant correlation between junk food and the other scales . </P> <P> A number of countries have adopted, or are considering, various forms of legislated action to curb junk food consumption . In 2014, United Nations Special Rapporteur on the right to health, Anand Grover, released his report, "Unhealthy foods, non-communicable diseases and the right to health", and called for governments to "take measures, such as developing food and nutrition guidelines for healthy diets, regulating marketing and advertising of junk food, adopting consumer - friendly labelling of food products, and establishing accountability mechanisms for violations of the right to health ." </P>

How health can be affected by eating junk foods