You can ask A.J. Jacobs why getting as healthy as possible can make for a messy personal life when he speaks Wednesday at Sixth & I Historic Synogague.

“My Life as an Experiment” is more than the title of A.J. Jacobs’ 2009 book; it’s a declaration of journalistic intent. The comedic writer’s newest release, “Drop Dead Healthy” (Simon & Schuster, $26) — an attempt to obey all nutrition, fitness and medical advice — follows in the tradition of 2005’s “The Know-It-All” (he read the entire Encyclopaedia Britannica) and 2007’s “The Year of Living Biblically” (he observed the Good Book to a T). Jacobs launched his latest quest, which involved visiting sleep scientists, acupuncturists and countless fitness gurus, after being waylaid by tropical pneumonia, and because his wife told him, “I don’t want to be a widow at 45.” Jacobs will appear Wednesday at 7 p.m. at Sixth & I Historic Synagogue ($10) to chat about losing his self-described “four-months-pregnant belly.”

What’s the secret to sticking with an exercise plan?
You’re not going to exercise if you don’t like it. You have to find something that is fun. … I love walking — all the time. I bought a treadmill desk and wrote this book on a treadmill. It took me about 1,200 miles. I never thought of myself as a walker. I was pretty happy with a sedentary life. But I find I have so much more energy now thanks to getting off my butt.

Do you still do high-intensity interval training?
I do HIIT training because it’s such a huge time-saver. I try to do that about three times a week. I go to the park and just sprint for 30 seconds, rest for 30 seconds, and repeat that eight times. The studies say this is perhaps a better workout than a half-hour of leisurely jogging.

What’s the worst thing you can do to your body?
Research shows sitting is really, really bad for you. In the book I think I say, “It’s like a eating a bacon donut every day for breakfast.” So, any movement we can do is good — even fidgeting in your chair is better than sitting still.

Is it strange to have people approach you now for health advice?
I like that role. I didn’t go to medical school, but I have read a lot. I think a lot of people ask me about things that are just dubious junk science. It’s pretty easy to dismiss those, even with a simple Google search. You don’t need a colonic. You don’t need to shoot water up your butt every month.

Did you think doing this set a good example for your sons?
They exercise their thumbs a lot with their [Nintendo] DSes. I like to incorporate exercise into everything I do. When I’m talking to them, I squat down to eye level with them, so we’re eye to eye, and then I stand back up. I ended up doing 50 squats a day just talking to my kids.

What was the most painful part of doing this book?
I did try to do cleanses and found them horribly unpleasant. I was so hungry I was salivating at the site of lettuce. The HIITs workouts are no walks in the park — they’re pretty painful. I figure that with ripping off the Band-Aid, you can do it slowly with a little bit a pain, or rip it off all at once. I rip it off all at once.