What Happens When You Do 100 Crunches Every Day For A Month?

As the video opens, he’s at more than 20 percent body fat, with a 37.5-inch waistline. It’s actually his second attempt at a sit-ups challenge; the first time he tapped out after the eighth day because he was too sore.

He also mentions that he’s changed his diet, dropping to around 1600 calories a day, which he cites as key to transforming his body.

After a brief training montage, he reveals that he lost 3.3kg after the first 15 days. (It’s also worth noting that for the first week he was also, separately, challenging himself to eat a dozen eggs a day.) It’s also around the halfway point that sit-ups started getting really easy, so he started mixing in other moves; he recommends the elevated leg crunch as a challenge.

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By the end of 30 days, he’s lost 6.3kg and dropped 3.5 inches from his waistline—but there’s a caveat. Most of that, Simple Man says, is attributable to changing his diet and drinking lots of water. “When getting abs, I think it’s about 90 percent diet, 10 percent exercise,” he says. He didn’t come away with washboard abs, but says he’s still impressed with the results. Overall, it’s a good reminder that even small changes can have an effect over time.

But the situp might not be the smartest ab move for you to do, if you take a challenge like this, says MH’s Ebenezer Samuel, C.S.C.S. “Situps aren’t bad and they’re oft-demonised,” Samuel says. “But before you do the situp, make sure you master the hollow hold. A key function of your abs is pulling your ribcage tight to your body, and the hollow hold teaches this. Doing this before situps lays the groundwork for a better situp.”

This article originally appeared on Men’s Health