Isaiah Mustafa, better known as the “Old Spice Guy,” may be buff, but he has a weakness: gluten. The star of the “Man Your Man Could Smell Like” ad, which recently won an Emmy for Outstanding Commercial, has spoken publically about his decision to remove gluten from his diet—and how difficult the detox has been.

“Right now, I’m vegan-cleansing: no processed sugar, no caffeine, no alcohol, no animal products and no gluten. I never knew what gluten was before. Now I know exactly what it is, and it’s everything I want!” he told the Hollywood Reporter in July.

Mustafa also mentioned his new diet on “The Tonight Show with Jay Leno,” declaring gluten the “tough one” to eliminate.

It’s unclear whether Mustafa is still avoiding gluten; however, his experience is a testament to the challenge of going gluten-free. Based on his struggle, others may be convinced to research the gluten-free diet, and its underlying medical need, before going gluten-free.