As medicine can offer little for the GMB patient, his or her best hope could be in a drastic change of diet that excludes all meat and cheese—but also nuts and soybeans.

All these foods feed two essential amino acids—methionine and tryptophan—that drive the cancer

once they have started to metabolize abnormally.

Although amino acids are vital for our growth and survival, they can become lethal in cases of GMB, especially when there is a sudden loss of a key enzyme, says Arnab Chakravarti at the Ohio State University’s Wexner medical centre.

In an extreme situation such as GMB, it could be the difference between life and death for the sufferer to stop feeding the two amino acids. Foods rich in tryptophan and methionine include cheese, lamb, beef, pork, chicken, turkey, fish, eggs, nuts and soybeans.