Channing Tweeddale has had to buy a lot of new shirts over the past 15 months.
As the 15-year-old Taupo-nui-a-Tia College student has pumped iron and downed protein, carbohydrates and supplements to build muscle, he's found it's not just his body that's changed. His wardrobe has had to change, too. His bulging chest and shoulders mean he doesn't fit any of the shirts he had before he began to body build.
"All of my clothing has sort of changed pretty fast, but it's all right.
"Especially the last six months I've really pushed it and I've had a lot of growth since then, I've put on about 20kg since last year."
Channing has only been body-building for 15 months, but shortly after he took up the sport he had encouraging results, scoring second place in last year's International Natural Body Building Association's South Pacific Championships.
In just over a week's time he'll be competing at the championships again, at the Great Lake Centre in Taupo, and he's hoping for a top placing.
Channing competes in the teenagers' (under-19) division and says he's not sure how many others he'll be up against this year. In 2011 there were only three entries; this year there could be many more.
He said although body building was an unusual pursuit for people his age, since he had got into it, he had also brought along several of his friends to Bodyworx Gym where he trained, although he added they preferred to improve their fitness, not bodybuild.
"They all sort of get into the gym because of it, but they think I'm a little bit overboard."
Channing first got into body building through family.
His cousin Frank Carroll trains him and he said a lot of the people at Bodyworx, such as fellow natural body builder Tim Moore, inspired him to pursue it.
Natural body builders do not use anabolic steroids or hormone enhancers to build muscle, hence the name of the competition.
"It's all about the nutrition and you mix your strength training and it's all about gaining that size and proportion in body building, trying to get the biggest or best looking body."
Channing trains five or six days a week for about an hour to 90 minutes at a time, lifting different weights to train all the different muscle groups, such as the lateral trapezius muscles that run from his neck to his shoulders, to the quads and hamstrings in his legs.
It's a lot of work, but Channing enjoys it. He has little time for anything else, so it keeps him out of trouble, too.
"That's what I look forward to every day is that one-and-a-half hours in the gym."
While part of building big muscles means lifting big weights, Channing also has to pay close attention to his diet, saying it is probably the biggest factor, especially in the lead up to a competition when he is zealous in his approach.
He cooks much of his food himself and takes chicken and rice for his school lunches. When he's not training hard, he eats what the rest of the family eats.
"At the moment, breakfast, lunch and tea is eggs and fish, eggs and chicken, and that's it really, that's all I eat ... for me that's the most important thing, that I eat well during the day so everywhere I go I'm always worrying about what I'm eating."
In the lead-up to the competition he'll also have a spray tan, cut out carbohydrates temporarily and lower his fluid intake to make his muscles appear more defined.
Channing has just one minute on stage alone at the championships to go through his poses and impress the judges, so he has to make the most of it.
And after the competition he plans to eat and drink whatever he wants, saying he's looking forward to getting into some pizza.