Constrained Carbohydrate Common Denominators: Pt 2 The Zone

In the first part of this series, "Constrained Carbohydrate Common Denominators", we introduced the goal of finding some "low-carb" nutritional guidance that can be syndicated to the broadest possible audience. To review, this message is not intended for people who are already following paleo or primal lifestyles, sophisticated self-quantifiers and nutrition geeks, or Cross-fit super-people, and it is meant to have relevance across the socioeconomic and educational achievement spectrum. We accept the view that everyone falls somewhere on the more-or-less continuous spectrum of perfectly regulated blood sugar to extreme cases of metabolic syndrome and diabetes. The goal of this exercise is to find a dietary prescription, which combined with the sort of physical activities anyone can incorporate into their regular life, moves one down this curve, towards a functioning metabolism and a normal weight. In some cases, weight loss will be an important side-effect but it is general well-being and avoidance of the diseases of modern society that is the primary success criterion. Although we don't view food 'addiction' as a root cause of the obesity epidemic; it seems to be an important part of the phenomenology of metabolic damage and it seems plausible that it has an important nonlinear feedback effect on this condition. An ancillary goal of this exercise would be to shift societal resources away from intensifying and fueling this behavior. It is important that the nutritional messages that are distilled are reasonably straightforward and require only basic background in food groups, macro-nutrients and reading nutritional information on labels. The guidelines cannot be overly precise or fiddly, and shouldn't require too much fine tuning. We are quite sympathetic to the view articulated by S. Andrei Ostric

...what I believe in regards to a philosophy regarding health and nutrition. You have to keep a lot of plates spinning to make it work ie low carb, avoid grains and sugars, avoid gluten, avoid processed foods, eat whole foods, eat your vegetables, get sleep, get exercise, get rest, control your stress, avoid fructose, don’t overeat, enjoy meals with family and friends. All those things are the plates, and you have to keep them spinning. Sometimes the plates break, and you have to start over, sometimes you need help get the plate spinning, sometimes you still break the plate and yo have to find a new way to do it. But most important is have fun (that is passion, involvement, and awareness) during the process, and remember its the whole that counts not just one plate.

Nevertheless, we are looking for some time-homogeneous solutions that are stable to perturbations. We start this survey with The Zone diet, created by Dr. Barry Sears. Our rationale is that The Zone has been around since the mid-90s, longer than most diets that would qualify as carb-constrained; it is very well known and has spawned a mini-industry of books, educational resources and products; most importantly, it is actually moderate in carbohydrates (suggested macro-nutrient ratio of 30-30-40 fat/protein/carb) so is closest to the 'Standard American Diet' and presumably would be a less severe modification for most people. The diet removes sugar and most simple carbs and replaces them with 'healthy' fats and moderate amounts of protein. An interesting differentiation of the Zone approach is the direct focus on avoiding systemic low-level inflammation rather than trying to influence fat metabolism. Of course, we are not attempting a comprehensive exploration of his diet here but are touching on a few key aspects. To fully appreciate the perspective, please see his website or Dr. Sears' interesting books, including "Toxic Fat" which we found refreshingly different in its perspective though obviously speculative in aspects.

 Dr Sears was gracious enough to respond to a couple of questions we sent him which, though, specific, to us strike at the essential differences between established low-carb dietary frameworks; we reproduce his answers here. (Please note that Thought-Fuel Company has no affiliation or business relationship with Dr. Sears or his company.)

Many low-carb diets focus on control of insulin and, more recent, leptin. When we asked if it was more important to optimize insulin or leptin he responded:

It's not optimal hormonal levels of either insulin or leptin that is the goal, but reduction of cellular inflammation in their target cells that compromises their signaling to the interior of the cell . Thus you are looking for an optimal anti-inflammatory diet that makes both insulin and leptin work more effectively. The best anti-inflammatory diet remains the Zone diet coupled with high dose fish oil and very low in omega-6 fatty acids. As you reduce cellular inflammation, the levels of insulin and leptin will begin to fall.

Putting aside all the fundamental questions about underlying biochemical mechanisms and how they interplay in the complex system of human metabolic health, there have been some critiques of the Zone diet approach. Here we mention a few of the more frequent ones: 1. The Zone diet is really calorie restricted, due to the caloric intake being calibrated to the 30% protein component -- which for most people equates to 300-500 calories. This doesn't strike us as a severe defect; There are a number of studies connecting calorie restriction with longevity and disease avoidance. Dr Rosedale's diet, which is much more 'severely' low carb, also emphasizes reducing food intake and lowering body temperature. 2. Unlike many of the currently vogue Primal and Paleo low-carb diets (though not all, eg De Vany), The Zone steers strongly away from the consumption of saturated animal fats. We asked Dr. Sears about this:

Saturated fats have a slight inflammatory effect because of their ability to bind to toll-like receptors and initiate an inflammatory response. However, omega-6 fatty acids are more inflammatory because they generate arachidonic acid. Both should be kept to a minimum by replacing them with monounsaturated fats (non-inflammatory) and omega-3 fats (anti-inflammatory).

Other more controversial aspects of the approach include the inclusion of soy as a protein source and the prescriptive macro-nutrient ratios for each meal. We view each of these as potentially positive in the 'common denominator' context. For many people without sufficient access to beef or dairy sources, even if soy protein is not optimal, it may be better than eating carbs. And as long as they don't need to be exactly adhered to on every occasion, a uniform macro-nutrient ratio per meal may be the easiest long-term rule to follow.

In future installments we hope to look at other low-carb diets through this same lens.
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