The results of a study appeared in June of 2021 about the effects of a high-fat vs a standard diet on mice. Mice that were fed a high-fat diet were more likely to experience changes in hair and skin, as well as signs of increased oxidative stress, which has been linked to tissue damage and an increased risk of cancer. The changes in hair and skin were observed in just four days. "High-fat diet feeding accelerates hair thinning by depleting [hair follicle stem cells] that replenish mature cells that grow hair, especially in old mice," according to one of the doctors who authored the study. We have heard news like this in the past.