The people who read the “Livin’ La Vida Low-Carb” blog are some of the most educated, informed, and thought-provoking people in the world of health. From laypeople to doctors, dietitians to nurses, the level of expertise and experience on everything related to diet, health, fitness and nutrition is as vast and deep as the ocean. As a simple layperson who has educated himself about these things since 2004, I am constantly amazed by the insightfulness of the people who read my blog, listen to my podcast and engage in the debate of ideas about what healthy living is. Every day is a new classroom experience for me as new information is made public and greater learning and understanding commences. Many times this happens whenever I receive an e-mail like one that was recently submitted to me by a registered nurse/certified diabetes educator about something she read and heard from Gary Taubes.
The bestselling author of the game-changing health blockbuster in 2007 called Good Calories Bad Calories recently came back on my podcast for an interview about his upcoming December 2010 release of Why We Get Fat And What To Do About It. This was what precipitated the feedback from the RN/CDE regarding her concerns about a phenomenon known as “the pizza effect” where blood sugar levels soar abnormally after eating certain foods. She was concerned that Taubes was erroneously putting the onus of high blood sugar and insulin levels on carbohydrate consumption when dietary fat could also be playing a role in this happening. Here’s what she wrote:
Thanks for posting this interview.
I hoovered up Good Calories Bad Calories in 2007, but the past two years I have been leaning more towards page 397 and seeing people with diabetes improve blood sugars and lose weight on very low-fat diets without “the cost of increasing fat accumulation and obesity.” [Line 6 page 397]. So I wanted to hear what Gary has to say about this three years later.
Gary does briefly discuss basal insulin levels and macronutrients in response to a question you asked him when he stated: “The key fact here is, it’s not just the short term insulin secretion, it’s the long term level of insulin in your blood and the relative sensitivity and resistance of the different tissues to insulin.” Agreed.
However, I do find that dietary fats increase late post prandial and basal insulin needs and this insulin resistance can be seen especially in people with Type 1 diabetes who monitor their blood glucose closely. People with Type 1 diabetes are unable to compensate for increased insulin resistance by upping their insulin production, so when they become more insulin resistant, their blood sugar levels run higher.
Hours after eating a high-fat meal, people with Type 1 diabetes often find their BGs remain higher than expected. For many years, this has been unofficially termed “the pizza effect” and this hyperglycemia often extends through the night and shows up as an elevated fasting BG the next day. Here is just one example from the Internet: “Seeing a graphical depiction of blood sugar after a high fat meal was shocking. We could see the blood sugar start to spike hours after we expected.”
So when determining post prandial insulin needs for people taking insulin, it’s not just carbs anymore, proteins and fats as well need to be accounted for to keep blood glucose in optimal range. See the presentations on this made at this year’s American Diabetes Association Scientific Sessions here and here.
This review of recently published research illuminates a fascinating immune/metabolic connection between dietary fats, inflammation and insulin resistance. This may be a major contributor to “the pizza effect” and may also explain why some people are, as Gary says in the interview, “beyond the point of no return” and do not lose a significant amount of weight when they follow a very low-carb/high-fat diet. High levels of inflammation may be keeping these people insulin resistant and this prevents them from losing weight.
This e-mail from the RN/CDE reminded me of the controversy stirred up by Dr. William Davis at “The Heart Scan Blog” earlier this year when he asserted that consuming fat like butter will raise insulin levels and make you fat (and he recently rekindled the debate again with his post last week entitled “Butter: Just because it’s low-carb doesn’t mean it’s good”). As a diabetes educator, my reader is greatly concerned that people like Gary Taubes may be overlooking an element in the management of blood sugar and insulin levels that is not directly tied to carbohydrate. When I forwarded this inquiry to him for a response, I had a sneaky suspicion he’d find the culprit is still the carbohydrates. Here was his response:
Interesting comments, but “the pizza effect” URL she provides is, indeed, pizza, which they describe as a high-fat food, when actually it’s both high-fat and high-carb. And much of the fat in pizza comes from soft cheese which may elicit a significant insulin response. So it would be interesting to know what happened to this man’s blood sugar had he eaten the cheese (and pepperoni, ideally) but not the crust.
As for the review article she linked to, there’s a similar problem. Carbohydrates are converted in the liver into saturated fatty acids. Dr. Jeff Volek from The University of Connecticut has published a lot of studies on how saturated fat levels in the blood are determined far more by the carbohydrate content of the diet than the fat. So is it the carbs? Could be.
Not that I’m saying she’s wrong, but the evidence she provides is based on the conventional wisdom (the review article talks about over-feeding and high-fat diets causing obesity) and then they draw their conclusions from that conventional wisdom, rather than understanding, for instance, where those serum saturated fatty acids might be coming from and what might actually be causing obesity.
Another thing she’s ignoring are the numerous clinical trials of Atkins studies, which are the best clinical evidence we have for what happens when people eat high-fat diets–they lose weight and they become insulin sensitive.
So, is it the fats or the carbohydrates that are leading to “the pizza effect” phenomenon where insulin spikes and stays elevated for hours on end? From what we know from the various studies that have been released in recent years, carbohydrates most definitely do this at varying levels depending on the fiber content and what they are consumed with. However, with dietary fat, under what circumstances would they have any measurable impact on blood sugar or insulin levels in the absence of significant amounts of carbohydrate or protein? I’m not seeing it happen but I welcome the input of anyone who has a theory they’d like to share.
For me, if you cut the carbohydrate and focus on consuming mostly fat with some moderate amounts of protein, then you are putting your body in a position to keep insulin levels low and, in turn, keep blood glucose levels stable. This will help create the right set of circumstances for your body to experience weight loss and reduced inflammation levels for optimal health. Avoid the pizza and other culprit foods that would lead to extended elevations in insulin levels and enjoy everything that livin’ la vida low-carb has to offer you. It’s as simple as that.