My neighbor and his wife are hooked on the diet, to the point they are now distributors, and not surprisingly it has worked well for them. You need to understand though, they are both in their early 60's, were sedentary, and borderline type II diabetic. They could have done just about anything to lose weight and it would have worked.
My neighbor is an engineer, and hasn't had much experience with biology and "such things", so he asked me to take a look at the diet components since I am a biomedical researcher. Honestly, it's just a different take on the protein shake diets first started in the '70's. You essentially replace two meals with their protein shakes (that are actually fairly balanced nutritionally speaking, including fiber and low GI carbs), start doing exercise and viola--you lose weight! Funny how that happens.
The big marketing ploy is that the diet is a "detox" diet. Now, being that one of the hats I wear is that of a toxicologist, I am getting pretty sick and tired of that buzz word lately. People, your liver and kidneys do all the detox you would ever need (if they didn't you'd be dead). Thus, while it may make you feel better, no colon cleanse is going to make them any better at their jobs. If you have a problem with that sort of thing, just eat more fiber.
There is, however; a grain of truth to their marketing, which is what makes it an ingenious money maker (wish I had thought of it first). Yes indeed, certain large poly-halogenated aromatic toxins (eg. insecticides like DDT) are stored in fat. Now, when you liberate the fat from adipose tissue from calorie restriction and/or exercise, those chemicals are indeed liberated as well. Eventually the lipids make it to the liver and normally most fat soluble toxins are made hydrophilic, and eventually excreted through the kidneys. Unfortunately the liver has a lot of trouble handling these large chemicals, and they can wind up getting past liver metabolism. Through what is called entero-hepatic recirculation, they wind up back in your body, stuck in adipose tissue somewhere else.
The idea behind the Isogenix "cleanse" is that soluble fiber binds up organics (including cholesterol) from bile, which is of course very well known, and allows it to be eliminated through the bowels. So, here is where the marketing magic comes in, they just include soluble fiber and a laxative in their diet, and low and behold, it isn't just a protein shake diet, it is a "detox" diet.
Nice marketing idea, but there really isn't any real world data to show it is of benefit. Keep in mind, that when these chemicals are stored in fat, they aren't doing anything--they are just there hanging out. Your liver usually has no problem with small amounts that "leak" out over time. Also, if there were actually a problem with what I'll term as "fat-loss induced toxicity", how come there is no mention of such a syndrome in any clinical or research publication? Heck, there are all kinds of people getting gastric bypass surgery, and losing 100's of pounds very quickly, and are they even in the slightest sick from toxin exposure? Nope. In fact they are MUCH healthier. The point is, that even though there are toxins in your fat, there aren't enough in there to do much if any harm. So, stop already with all the freaking-out and the worrying and the monkeys stealing my glasses about toxins. ("Glavin, mmhai!"--Professor Frink)
So you see, there is no magic with the diet. Really, it works because it restricts calories, and encourages you to exercise. Just common sense, the laws of physics, and biology at work. If you want to make your current calorie restricted diet a "detox" diet, just take some Metamucil, or eat oatmeal. They are a lot cheaper.
Just my 2 cents.
