Carbohydrate Loading Practice in Bodybuilders: Effects on Muscle Thickness, Photo Silhouette Scores, Mood States and Gastrointestinal Symptoms

A common practice among bodybuilders is the use of carbohydrate loading to improve physical appearance during competition, while limited documented data is available about this issue. The aim of the present study was to evaluate muscle thickness, mood states, gastrointestinal symptoms and subjective silhouette assessment following carbohydrate loading in bodybuilders. Twenty-four male bodybuilders were evaluated at the weighing period following three days of carbohydrate depletion (M1), and 24h of carbohydrate loading leading up to the competition (M2), stratified into: no carbohydrate load (NC, n = 9) and carbohydrate loading (CL, n =1 5). The silhouette scale, Brunel mood scale (BRUMS), muscle thickness (ultrasound), circumferences, and gastrointestinal symptoms (GIS) were evaluated at M1 and M2. The NC displayed no differences in muscle thickness and circumferences between M1 and M2. Body mass, muscle thickness (elbow flexors, a combination of biceps brachii/ brachialis muscle, and triceps brachii) and circumferences (chest, hip, thigh, arm, calves, and forearm) increased significantly (p < 0.05) in the CL at M2. There was a significant increase in photo silhouette scores (p < 0.05) in the CL at M2. There was no significant difference in mood states between groups or time. The most reported GIS was constipation: 7/9 (NC) and 9/15 (CL) during M1 and 6/9 (NC), and 5/15 (CL) at M2 with symptoms described as 'moderate' or 'severe'. Diarrhea was reported by 7/15 CL (4/15 as severe). These data suggest that carbohydrate loading may contribute to an acute increase in muscle volume and physical appearance, however, it needs to be better planned to minimize gastrointestinal symptoms in bodybuilders.