8:54 p.m.: Fifth juice. My stomach was growling so badly that I didn't care how terrible it tasted. Now I need to deal with a sugar high (and another sugar high) right before bed. I can't take this sugar. My body, starved of fat, is demanding grease and bread. McDonalds sounds like heaven.

10:30 p.m.: Final juice of the day. My body needs food, and I'm on the verge of buckling. The only thing stopping me? I dumped all my food out the day before the cleanse. Smart thinking there. Let's hope my roommates don't have anything to eat.

12 a.m.: I cracked. The only food left in the room was my roommate's fortune cookie left over from his lunch. I ate it. It was a tough call, but there was nothing else around, and if I left the apartment I was going to wind up buying a pizza slice. I feel much better now, though. Let's hope I don't sleep talk tonight.

Day 3

6:50 a.m.: Woke up again last night. This time it was at 4 a.m., but I was thoroughly convinced it was time for class, until I pulled myself out of my trance long enough to look at the clock. I haven't done this since I was in the eighth grade.

7:30 a.m.: First juice. I can't wait until 10; I'm too hungry. New York City smells of food. Every store, every street vendor, every trash can is emanating the most wonderful scent, and I can't go near any of them. I just keep telling myself, "Just one more day." And, again, I almost got hit by a bike.

9:20 a.m.: It suddenly occurs to me that a cute girl from my economics class yesterday may have been flirting with me, but I'm not entirely sure. I've become so focused on my hunger that everything else—including girls—is falling to the wayside. My aching stomach is a distraction.

10:15 a.m.: Second juice. I'm becoming more accustomed to the cycle now. Feel like crap, drink a juice, go on sugar high, crash, feel even worse, drink another juice, feel better. It's like the highs are getting higher and the lows lower.

11:30 a.m.: I learned from my roommate that I did sleep talk again last night. He described it as "gibberish, then words, then more gibberish" and said I sounded like I was "fighting a ghost." That's actually pretty accurate.

12:50 p.m.: Third juice and "lunch" with my girlfriend. She's trying to persuade me to break the cleanse. Partially because she thinks I'm killing myself, mostly because we're scheduled to get dinner with her friends tonight and see a pre-screening of The Muppets.

3:30 p.m.: Fourth juice. I could barely concentrate at my economics seminar today. This is partially because I had to go to the bathroom three times in an hour but mostly because my stomach is roaring. Thank God it's only a class; I don't know how I could do this if I had work. I'd get fired in record time.

5:15 p.m.: Fifth juice. Had dinner with my girlfriend and I got angry at her chewing her food slowly to taunt me. In reality, she was only eating. As my body gets hungrier, it's harder and harder to see things straight.

7 p.m.: Met for the movie. Had to explain to girlfriend's friends what my juice diet consisted of and they laughed at me.

9:30 p.m.: Sixth juice. Sitting through the movie was torture. I could barely concentrate because the smell of the popcorn was so strong. I had to leave twice to go to the bathroom. My feces are pretty much liquid now.

10:30 p.m.: Feeling numb, hungry, and worn-down, but I'm almost there. I felt a bit of elation, but I'm pretty sure it was just the post-juice jolt. I keep fantasizing about the greasiest foods imaginable: bacon, fries, really bad Domino's pizza. If I make it out of this, I vow never to eat another spoonful of sugar again.

12 a.m.: Sleep. My roommate is vowing to tape-record anything I say so he can hold it over my head later. I promise to sleep-smack him, and then I roll over. Throughout most of the cleanse, I've felt a dull ache in the pit of my stomach, but I think my coffee addiction is gone, though: no headaches today.

The first morning I woke up pretty hungry and lethargic. Then I got a huge bacon-and-egg sandwich from my local deli and ate it in five bites. I washed it down with a hot cup of coffee. It was glorious for 10 seconds, and then I had an upset stomach. While I lost five and a half pounds, at dinnertime that day I persuaded my friends to go to a local diner, where I had the greatest pastrami sandwich of my life. Five minutes later and I was still craving salt and grease like nothing else. But I'll give the cleanse one thing: After three days of consuming only liquid sugar, I never want to touch a Snickers or a Reese's Peanut Butter Cup again.

Also on Details.com
Rock-Star Yoga
True Blood's Joe Manganiello on How He Got Lean, Mean, and Hungry Like the Werewolf
Matthew Morrison's Body Project
Inside America's Male Body Obsession