Watch: man who lost 130 pounds surprise his parents

This is Lucas Irwin in May of 2012.

This is him on Dec. 10, 2013.

In just shy of one year – he didn't start losing weight until December of 2012 – Irwin went from 300 pounds to 170. How did he do it?

"95% of it was done through nothing but a 1350 calorie limit per day," he wrote on Reddit. "No foods were off limit, but I survived mostly on tuna salad, chicken with salsa, frozen vegetables, beans and rice, turkey/roast beef sandwiches, spinach, and eggs. After I lost 100 pounds I started walking to work (5 miles) for about 2 months until it got too cold outside."

Here's the best part – during the entire year, Irwin didn't mention anything to his parents. Not a word. So imagine their reaction when they saw him for the first time. Or better yet, watch it:

Only his sister was in on it. She's the one who filmed the unveiling.

When asked if he likes his new clothing options, the 5-foot-8 Irwin responded, "Yes I do, and it's very strange having 'how does it look?' be a criteria instead of just 'does it fit?' "

And he's not done yet. His goal weight is 150 pounds.

"The best part has definitely been the reactions of co workers and friends," he wrote. "I have people asking me for advice on almost a daily basis now, and I've seriously considered making it a career path (dietitian)."