Now, I haven't tried those other diets, but even without the other experiences I have to say that the zone diet is the best.  When I was strictly following it during my first year of my new, healthy life, I had tremendous energy, I slept well, I woke up feeling great, and I lost between 1.5 and 2 pounds of weight each week.  It was fantastic.  Screw Atkins, it makes you sluggish and gives you mood swings.

Overview
The zone at its core is a restructured food pyramid.  Instead of that counterproductive triangle you see on the side of your ever-so-trustworthy cereal box, the zone recommends that 40% of your calories come from carbohydrates(veggies and friuit - NO bread or rice!), 30% from protein, and 30% from dietary fat.  For those of us trying to bulk up, more protein should be added.  The extra protein probably affects energy levels, however.  Oh yeah, and you have to eat 5 or 6 times a day and drink lots of water.

Fat???
Yes, fat - fat in food does not turn into fat in your body.  Fat's role is essentially to slow down the absorption of carbohydrates in your metabolic system.  Fat is also a natural apetite suppressant.  Can you eat an entire bag of microwave popcorn?  Of course you can - hell, you could even eat two.  Popcorn, while very healthy, is misleading to your appetitie because it's very low in fat.  Of course, not all fat is good for you.  Fats that are acceptable to the zone are polyunsaturated fats, such as those found in avocados, olives, and nuts.  Always try to use olive oil - it tastes good and it's good for you!

What's wrong with carbs?
Carbohydrates provide the body with energy, which is just super!  Carbohydrates break down into sugars in your stomach and are converted into energy.  The problem with them is that when you have enough energy, whatever you have left isn't flushed out of your system.  Instead, the excess is converted into FAT and stored away, and that is LAME!  With the zone, moderation is the key(isn't it for everything?).  You eat enough carbs to sustain your energy until the next meal.  You don't eat just any carbs, either.  Fruits and vegetables that are high in fiber are recommended.  Fiber helps slow down the absorption of the carbs.  On the other hand, carbohydrates that are high in sugar and starch should be avoided.  Such no-no's include bananas, bread, pasta, potatos, and corn.  I know, it breaks my heart, too!

Protein is all good
Not much to say about protein - it's essential for muscle maintenance and growth.  Lean protein, like chicken breasts, are the preferred form.  Protein from red meat is way hiogher is calories, not to mention cholesterol.  It would be wise to limit the instake of red meat.  When I want to really go hard-core on muscle building, I like to consume a lot of flank steak.  It's a very lean cut that will give me the protein and calories needed, but it can be a tough chew if you take it anywhere past medium doneness. 

Control your hormones!
The zone's balanced approach to the components of food is geared toward maintaining hormone levels.  It's about insulin and glucagon.  Have you ever gone out to lunch for Italian and then come back to the office ready for a nap?  The high-starch bread and pasta from lunch spiked your insulin levels.  It gave you a quick sugar rush because it was absorbed rapidly.  What happens after a spike - a crash.  Insulin makes the body store extra energy as fat.  The rush of insulin was generated to manage the huge injection of fuel into your system. 

Glucagon is the hormone that causes your body to burn fat.  Protein is one thing that will cause the body to convert your fat into energy.  This is the methodolgy behind the Atkins diet.  Hey, if you eat nothing but protein and generate nothing but glucagon then you should lose a lot of weight rapidly, right?  Well sure it works, but such a hormonal imbalance will affect your mood and energy.  You'll look good, but feel like shit. 

The zone keeps your hormones balanced at an optimal level, givng you high energy levels all the time.  You'll feel better, sleep better, and weight loss occurs at a healthy level.  Though I no longer follow the zone as strictly as before, when I did I can attest that it was probably the best I ever felt.  I was able to get up every morning early, feeling like a million bucks.  These days I wake up feeling sluggish, and on weekends I wake up at noon, still feeling sluggish. 

How do you measure?
That's a damn good question.  I first got introduced to the zone through Zone Perfect Delivery.  It was a personal catering service.  It took care of all my meals for an entire month.  I'd have to say it was quite terriffic, but I stopped because the price was raised and my disposable income was severely hindered by debt I got into from the stock fallout.  The zone delivery people first sent me a consultant to do a personal assessment.  He showed me a simple technique for measuring.  Prepare to be surprised, but also keep in mind that you're eating 5 or 6 times a day, so that's about every 3 hours.  To measure your three primary meals - breakfast, lunch, and dinner - use your hand.  the amount of carbs taken in should be about the size of your fist.  The protein should be half that size(about the size of the palm of your opened hand, sans fingers).  The amount of fat should be about the size of the tip of your thumb, from the end to your joint. 

This has been a brief primer on the Zone, based on personal experience. Visit http://www.zoneperfect.com/site/content/guide_01_intro.asp to learn more. After going through that and trying the Zone out for yourself, you'll probably find that what I've outlined above is all you need, however it is important to understand it all in context.

Someone has suggested that I also point you to http://www.Zonedietinfo.com and http://www.zonedietathome.com. Zone Diet at Home is probably the same service I used back in 2000-2001 under a different name, but back then it was $20 a day. Now it's $35. Yikes. If you've got the scratch though, it definitely works.