Hi Steve
No, it is never acceptable to have breads made of refined flours in any stage of atkins, except occasionally in maintenance. The reason this is so, is because not all carbohydrate sources are equal to your body. Some carbohydrate food is so dense with sugars and starches, that it much more closely resembles pure glucose than others. For example, your body would break down 9 grams of that piece of bread much quicker than it would 9 grams of carbs from nuts or berries.
The quicker a carbohydrate is broken down, the quicker it enters your bloodstream as fuel. High blood sugar is unnatural state for your body to be in. So, your body then normalizes its fuel reserves by triggering an excessive release of insulin. The insulin rushes the glucose off to your bodies cells, and whatever cannot be used during this process (and chances are, its most of that bread you just ate) is rushed off to storage: your
fat cells. How detrimental a carbohydrate source is to your blood sugar (and how greatly it effects insulin production) is quantified by a system called the Glycemic Index (or Glycemic Load, which multiplies a carbs GI by its weight in grams).
Insulin is the mother hormone when it comes to controlling your bodies fuel levels, fat stores, and hunger cravings. Insulin either directly or indirectly controls these processes. Understanding the link between insulin, overweight, and weightloss is crucial to understanding why atkins works so beautifully. Keeping insulin levels low and stable not only prevents your body from storing
additional fat, but also encourages your body to use the existing stored fat as fuel. Whereas, when insulin is high, your body fights to hold on to fat stores (making you feel miserable in the process).
Until now, it has been believed normalizing weight is linked with deprivation and misery. When the insulin link is examined, brought into the equation, and eating habits are tailored appropriately, we can see this isn't so. These reasons are why atkins is not only so effective, but also enjoyable and fairly easy to maintain. It is grounded in scientific reality. It notes the details regarding what works, and ignores nutritional dogma. A calorie is not a calorie, macronutrient sources are different for a reason. Fat does not make you fat, excessive insulin triggered by high refined carbohydrate dietary intake makes you fat.