We at Refinery29 are fans of solid food — and we're not buying the unscientific claims of juice-cleanse proselytizers. When our intrepid guinea-pig-in-residence Lucie Fink decided to embark on a five-day juice cleanse to observe how she felt, she was skeptical but curious. "With the way these cleanses are branded, it's no wonder that people want to try them," she observes in our video, above. "They use words like 'invigorate,' 'restore,' 'nourish,' 'heal.' They claim that you'll have more energy, and that you'll feel more alert and 'alive' — so, once and for all, I want to see what going on a juice cleanse does to my body."Lucie quickly realizes she hadn't known what she was in for, and meets with a nutritionist for some real talk about liquid diets. "Your liver and your kidneys are self-cleaning," Christy Harrison, RD, CDN , explains. "They're not like filters in the sink that get clogged up with gunk and need to be cleaned out."A few other cleanse reminders , courtesy of Harrison, that we'll add here:• Symptoms such as headaches, dizziness, and nausea don't happen during cleanses because "impurities" are leaving your body — they happen because your blood sugar is low.• Unless you have a serious intestinal disorder, you have no medical need to "rest" your digestive organs by depriving them of solid food. That's not how digestive organs work.• Detoxes and cleanses can trigger relapse in those with histories of eating disorders or risky weight-control behaviors.Watch the video to find out how Lucie handled her juicy experiment, and what she learned in the process.