Matt Damon says cutting one thing out of his diet got him down to his 'high school' weight

Matt Damon says his latest role required a strict routine that left him lighter than he's been in years.

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• Matt Damon, 55, says he made a big diet change to prepare for his latest film, "The Odyssey."
• He said cutting out gluten helped him slim down to 167 pounds, a weight he hadn't been at since high school.
• Experts say gluten-free diets are not universally necessary for weight loss or better health.

Matt Damon, 55, says...