A British study suggests that a diet of burgers, chips and cake programmes your brain to crave even more for foods that are high in sugar, salt and fat content - just like drugs.
Over the years, junk food can become a substitute for happiness and can lead bingers to become addicted.
Paul Kenny, a neuro scientist, carried out the research which shows how dangerous high fat and high sugar foods can be to our health. "You lose control. It's the hallmark of addiction," he said.
Researchers believe it is one of the first studies to suggest brains may react in the same way to junk food as they do to drugs, reports the Telegraph.
"This is the most complete evidence till date that suggests obesity and drug addiction have common neuro-biological foundations," said Paul Johnson, Kenny's work colleague.
Kenny, who began his research at Guy's Hospital in London, but now works at Florida's Scripps Research Institute, divided rats into three groups for his research, due to be published in the US soon.
One got normal amount of healthy food to eat. Another lot was given restricted amount of junk food and the third group was given unlimited amount of junk, including cheesecake, fatty meat products, and cheap sponge cakes and chocolate snacks.
There were no adverse effects on the first two groups but the rats who ate as much junk food as they wanted became very fat and started bingeing.
When researchers electronically stimulated the part of the brain that feels pleasure, they found that the rats on unlimited junk food needed more and more stimulation to register the same level of pleasure as animals on healthier diets.