No doubt: The diet approach advocated by the late Dr. Robert Atkins was a heck of a lot closer to an ideal diet than the knuckleheaded advice emitting from the USDA, American Heart Association, American Diabetes Association, and the Surgeon General's office.
But having just spent a week with Atkins low-carbers, here are some common errors that I see many make, errors that I believe have long-term health consequences, including impairment of weight loss.
Excessive consumption of animal products--Non-restriction of fat often leads to over-reliance on animal products. Higher intakes of red meats (heme proteins?) have been strongly associated with increased risk for colon and other gastrointestinal tract cancers. It is not a fat issue; it is an animal product issue. We should consume less meat, more vegetables and other plant-sourced foods.
Consumption of cured meats--Cured, processed meats, such as sausage, hot dogs, salami, bologna, and bacon, have a color fixative called sodium nitrite, an additive that has been confidently linked to gastrointestinal cancers. Risk is likely dose-dependent: The more you ingest, the greater the long-term risk.
Overconsumption of dairy products--Dairy products, especially milk, yogurt, cottage cheese, and butter, are potent insulinotropic foods, i.e., foods that trigger insulin release. There can be up to a tripling of insulin (area-under-the-curve) levels. This is not good in a world populated with tired, overworked pancreases, exhausted from a lifetime of high-carbohydrate eating.
Too many calories--While I agree that "a calorie is a calorie" and "calories in, calories out" are faulty concepts, I have anecdotally observed that long-time low-carbers often trend towards unlimited consumption of food, a phenomenon that seems to result in weight gain, especially in the sedentary. I wonder if this is a reflection of the insulinotropic action of dairy products and other proteins, compounded by the poor insulin responsiveness that develops with lack of physical activity. Factor into this conversation that lower calorie intake extends life, probably substantially (Sirt-2 activation and related phenomena, a la resveratrol). If lower calorie intake extends life, unlimited calorie intake likely shortens life.
Please don't hear this as low-carb bashing--it is not. It is a call to improve diets and not stumble into common traps that can impair heart health, weight loss, and longevity.