Not long afterwards, he revealed that he felt that he was living on 'borrowed time' and that he had made several lifestyle changes - including becoming a vegan - in order to improve his health.
Now, Smith has posted an update on his progress and to say that his weightloss is dramatic is something of an understatement.
"6 months ago yesterday, I had a heart attack," he said in a post on Instagram. "The Doctor told me to lose 50 pounds, but I have a problem doing what I’m told. So I lost 51 pounds instead."
He revealed that he had lost the weight via Weight Watchers and was now at his lightest weight since high school - adding that he was inspired to follow a plant-based/vegan diet by his daughter, Harley.
Read his full post below:
This @weightwatchers Ambassador is thrilled to announce that I’VE LOST 51 POUNDS! Six months ago from right now, I was in the hospital recovering from a heart attack I’d had the night before. When I went to my Doctor a week later, she told me “The best thing you can do for yourself now is to lose 50 pounds.” Half a year later, I can report that I followed Doctor’s orders: I started at 256 and now I weigh 205. This is the lightest I’ve been since high school! My hope now is I can slowly lose another 10 with #weightwatchers and get down to my birth weight of 195! But for now, I’m ecstatic to have reached this chunky milestone! I wanna thank #pennjillette for his book #presto, @raycronise for getting me started with his potato famine, and the good folks at #weightwatchers for their app-based program that made it easy to keep track of and control my eating! And I also wanna thank my kid @harleyquinnsmith - the little vegan astronaut who explored this meatless/milkless galaxy ahead of me, leading by example. Since I never wanted to see the inside of a hospital ever again, I simply copied the Kid. So this wasn’t a diet: these results came from a total lifestyle change of eating solely plant-based foods (which is tough because I hate vegetables). But mostly, I wanna thank all of you as well - for the kind and encouraging words along the way. Never underestimate the power of positive feedback: you folks telling me I looked better or healthier helped me stick with it. An encouraging word can really make a difference in someone’s life and your compliments kept me going! And just look where I went! #KevinSmith #WWambassador #WWFreestyle #WWFamily #WWBros #weightlosstransformation #weightloss #WWCommunity #ad *People following the Weight Watchers program can expect to lose 1-2lbs per week.