If you have a hard time giving up your favorite junk food, a new study says that it’s not just a lack of willpower, finding that quitting highly processed junk food can cause withdrawal symptoms that are a lot like those experienced by drug addicts. University of Michigan researchers asked 231 study participants to report any physical or psychological withdrawal symptoms after cutting down on or totally giving up junk foods over the past year. They reported experiencing sadness, tiredness, cravings, and increased irritability in the first two to five days after quitting junk food, with the symptoms eventually fading after those first few days. That’s similar to how drug withdrawal works, with the most noticeable symptoms in the first week after stopping drug use, although they can vary depending on the type of drug and length of addiction. The researchers also found that the more intense the withdrawal symptom from junk food, the less likely the attempt to stop eating it would be successful.