Dr. Atkins says that all calories are not created equal: Grams of carbohydrate are not equal to the equivalent grams of protein. Similarly, carbohydrates are not created equal, either - which is an often misconception among low-carb dieters.
Carbs' impact on your blood sugar is ranked on a scale called the "Glycemic Index." The most common sugar, glucose, has a G.I. value of 100 - very, very high - and most certainly will cause blood sugar levels rise, followed by a severe drop. A G.I. value below 55 makes it a low blood sugar impact food - the food will be digested slowly. Intermediate G.I. foods fall between 55 and 70, and high G.I. foods are those above a 70.
Milk's G.I. is 27 for full-fat, or 32 for skim. Milk tends to have 11-12g of carbs per cup. This makes it a pretty low glycemic food, and honestly, if your carb allowance will let you have it, why not have a cup everyday? The distribution of calories among fat, protein, and carbohydrate is quite even, and plus, milk provides a good amount of calcium, and iron, and it tastes really, really very good
So if you're off induction, I suggest that if you miss it, add it back onto your diet!
Plus, studies show that calcium-enriched foods help speed weight loss! Yogurt is also a good substitute - at 3-4 carbs per cup (the active bacteria eat up the other 10 or so), and at a G.I. of 17 (the artificially sweetened ones) it is one of the healthiest foods out there.