Many bodybuilders use anabolic androgenic steroids (AAS) to potentiate muscle mass gain as a result of specific resistance training and nutrition. The case we describe hereafter outlines alterations in body composition of an amateur bodybuilder during his pre-competitive period (11 weeks). The Participant was a 28-year old Caucasian male who was aiming to participate in his first bodybuilding competition under the “Men’s Physique” category. The Participant self-administered AAS for the whole pre-competitive period, followed a 13 set-meal plan consisting of 10 daily meals interspersed by approximately 2 h, and performed six high-volume resistance-training sessions a week. Body mass and anthropometric variables were measured at the beginning, during and at the end of his pre-competitive period. Dietetic analysis revealed a reduction in protein intake at the 10th (% decrease: ?51.3%) and 11th weeks (% decrease: ?64.5%) and in calorie intake at the 10th (% decrease: ?57.9%) and 11th weeks (% decrease: ?59.5%) in comparison to the 1st week. As a result, the Participant reduced both total body mass and fat percentage. However, there was a reduction in absolute fat free mass, despite the use of AAS. Apparently, the combination of excessive volumes of training with inadequate protein consumption was responsible for this outcome.