If you really like junk food, you know how hard it can be to kick the habit. Foods can soothe you. We usually believe that it’s because of the memories associated with the foods or the presence of flavors we like. But we’re wrong.

Doctors have known for a long time that food addiction is real. It’s not a failing of willpower that makes us pick up snacks. It’s not simply that, when you buy food while you’re hungry, you make high-calorie choices. People who can’t stay away from junk food — despite their best efforts — may have the same biological propensity as people who suffer from drug problems. The brain’s reward center is stimulated the same way with drugs or food. And, just like any other form of addiction, over time the brain begins to have less and less of a reaction to the stimulant and therefore craves more and more of it. Some people, without the inclination for addiction, can have a serving of chips and be perfectly content. Other people can have a serving of chips and spend the rest of the day highly aware of the fact that there are more chips that could be eaten.

Moreover, being exposed to the foods, even without eating them can make people crave them more.A study earlier this yearfound that having people see, touch and smell a food made them willing to pay more for it and buy larger amounts — regardless of whether they were junk food addicts. The researchers saw that it wasn’t because being exposed to the food made people hungrier, and therefore willing to pay more. With nonaddictive foods, the amount that participants were willing to pay remained stagnant throughout their exposure.

Now, research released last month appears to have proven that people have withdrawal symptoms when giving up junk food. Participants reported being tired, irascible and sad while experiencing cravings for a period after giving up their favorite foods. The findings are interesting and would greatly impact our understanding of addiction if strengthened with more research. The research was flawed in that it was conducted through retrospective self-reporting. People’s memories are not perfect. A better was of tracking people’s feelings in real time needs to occur before we can attribute weight to the study.

The researchers on the study were quick to say that they weren’t equating the severity of the symptoms to those of quitting drugs. Drug addictions cannot be trivialized. Quitting an addictive drug is undoubtedly harder than quitting pizza, even though pizza is the most addictive food. However, if people are genuinely experiencing withdrawal, it could change approaches to dieting.