The 26-year-old is out of contract at the Emirates at the end of the season and was on the fringes of Arsene Wenger's Premier League plans up until the last month.
After being given a first-team chance, Wilshere has impressed with his performances for the side and has now started their last six league games in a row, getting on the scoresheet during their controversial 2-2 draw with Chelsea in midweek.
The England international is now believed to be closing in on a new deal and thinks that a change in lifestyle has been instrumental to his improved form of late.
"I've been dairy- and gluten-free for six weeks," he said in an interview with The Guardian. "My kids since birth gave been dairy- and gluten-free. The few times I've had dairy in the hotel I've had an upset stomach.
"But I just cut it out completely and I think I look better. I've certainly lost a little bit of weight. I'm leaner and probably a little bit fitter as well. I feel I can last longer. At the end [of the draw against Chelsea] when we scored the second goal I thought: 'Come on, we can go again.' I felt good.
"For myself it's good to know. It gives me belief in my body. I've never questioned it. I've never thought before the game: 'I'm a bit tired today' and this is the third game in six days. I was ready to go. I know my body well. I know the right foods to eat. I know the best way to recover and get the right amount of sleep. I've done that over the years and I think now that I am in the best shape that I have ever been."
Wilshere has been with Arsenal since the age of nine but has endured an injury-prone senior career, having spent more than 1,000 days out on the sidelines.