A friend of mine was in the habit of drinking lots of water with lemon (instead of soda, etc.) and her dentist told her that it was ruining her teeth - it's too acidic. I can only imagine what a dentist or a doctor would say about a lemonade cleanse (I'm deliberately not linking to either one of these diets).
If you want to cleanse your body, drink lots of water, eat lots of food in its natural state - mostly plants. Don't eat things out of the middle of the grocery store - like Oreos and cereal. Stick to the stuff on the perimeter - produce, meats, dairy, or things like oatmeal, whole wheat pasta, etc. that are un-fooled-around-with.
If you want to lose weight, try Livestrong.com. I lost 50 pounds before I got knocked up, and I ate real, normal food. I ate lots of chicken and lots of vegetables, in much smaller portions than I was used to, but I gradually tapered down from the way I used to eat to a much healthier number of calories.
Here's the Amy diet - for free, as opposed to most diets out there. This is what I ate in a typical day. It was healthy, filling, nutritious, and it WORKED. It's important to note that I measured out servings and weighed things - especially meats. I avoided cheese almost entirely.
Breakfast: Oatmeal (made with half milk, half water) with natural sweetener (honey), a piece of fruit, coffee. Or an omelet made with one egg and one egg white, and a whole bunch of veggies, a piece of toast with spray butter, and coffee.
Lunch: A big salad with as little dressing, cheese, and croutons as possible. Or a bowl of Progresso light soup and a half a sandwich (light bread, no cheese, no mayo - use mustard instead). I ate a lot of those Morningstar Farms meat substitute thingies. Often I had a chicken breast sandwich from Subway with lots of veg and a half a bag of baked chips. Fruit. Water.
Dinner: Load up on cooked veg, go easy on starch - 1/2 cup serving of rice or potatoes, small baked potatoes with spray butter being the best option, 4 ounces (MEASURE IT) of chicken, fish, or beef. The average chicken breast you buy in the store weighs 8 oz. You must measure and weigh it, or you're getting twice what you think you are. Fruit.
Dessert: Frozen yogurt almost every night. You have to live a little.
In between I drank water and iced tea with a TINY bit of sugar. I tried to avoid chemicals (except that damn spray butter, and my Coffeemate creamer - I'm an addict to those two, but no Nutrasweet, etc.).
You don't need to follow some "plan" to lose weight. You just need to eat sensibly and watch your portions. You don't need to drink some bizarre concoction to cleanse your body - water cleanses your body. Fiber cleanses your body. Your body isn't meant to be clean inside, anyway. If you want to cleanse yourself of toxins, stop eating them! Don't drink diet soda or eat things you can't pronounce.
I'm pretty much still eating this way, except with larger portions for the baby. I was down to 1450 calories a day, and you can't sustain a pregnancy on that.
Please don't fall into the Fad Diet trap. There is no such thing as a quick fix. You have to change your eating habits permanently to enjoy permanent weight loss. If you do manage to survive a lemonade cleanse and you then begin to eat the way you used to, any weight you lost is going to come right back - probably in exactly the same amount of time that it took you to lose it. Science has proven that yoyo dieting like that is especially bad for you.
Just don't. Be smarter than the hype.
