Zone bars or Zone Perfect Nutrition Bars as they are marketed creates an easy and effective way of getting a perfect balance of carbs, protein and fats. The manufacturers might be exaggerating when they say that it will only burn stored body-fat for 4 to 6 hours after you have eaten it, but it has good value in it.
The Zone bars also have got the addition of 19 essential vitamins and minerals to ensure good health and fast muscle repair. The manufacturers are very specific when they openly state that the addition of the unique Omega-3 fatty acids, which are only, found in freshwater fish makes this product stand on its own.
It would depend on how often one would take these bars as the size of your budget would be a consideration if you were having them more than one a day. However it should be kept for occasions, which are beyond your control, and you cannot take time for the required snack or meal.
It is certainly not a perfect replacement for a good quality meal but it can fill the gap very nicely and very effectively. There is nothing that can replace a well-prepared and calculated meal. The ingredients of a Zone bar come close to the nutrients that you might get in a small meal but that does not mean that it should be a permanent replacement.
Zone bars are often kept close at hand by diabetics who require regular meals at specific times. But any good bodybuilder that want to ensure the proven results that it takes to make muscle, the lifestyle would need to be as strict as a well-controlled diabetic on insulin in order to get muscle gain on a permanent basis.
This makes something like a Zone bar or any of the other protein bar equivalents something that should be in any good body-builders kit bag. As mentioned above results come from planning correctly but we all know that life at the best of time is unpredictable.