He recently published a book titled Your Personal Paleo Code, which also happens to be a New York Times bestseller. The primary goal of the book is to help you develop a diet and lifestyle that support health and well-being by starting from a generally healthy template and personalizing it to your needs. Let's have a look.
Kresser opens with the poignant story of his own health problems, which began with an infectious illness in Indonesia and several courses of antibiotic therapy. After years of struggling with the resulting symptoms, trying a variety of diets, and finally accepting his condition, he was unexpectedly able to recover his health by adopting a personalized Paleo-like diet that included bone broth and fermented foods.
Chapter 1 focuses on the rationale for eating a Paleo diet and adopting more "ancestral" lifestyle patterns in key areas. It rests primarily on the following core arguments:
- We're sick today. Something ain't right about our current diet and lifestyle.
- Early agriculturalists were less healthy than their hunter-gatherer forbears.
- Our hunter-gatherer ancestors were tall and healthy.
- Contemporary hunter-gatherers are healthy, and their health declines when they modernize.
Kresser is quick to acknowledge that certain contemporary cultures have maintained good health on diets heavy in grains, legumes, and dairy, and that this probably results at least in part from cultural and genetic adaptation to agricultural foods. This is part of his rationale for experimenting with these foods as part of a healthy diet.
One thing that I think could have buttressed this chapter further is more discussion of how modern biomedical research has supported many of the core elements of the Paleo approach, such as eating minimally refined food, higher protein and lower calorie density for weight control, and nuts, fruit, vegetables, and wild-caught fish for overall health. The Paleo diet controlled trials would also have been relevant here. But the book is not really designed to be academic-- it's designed to offer a practical diet and lifestyle strategy for regaining and maintaining health, so let's move on to the next section.
The core strategy of the book is simple but powerful: start with a baseline diet and lifestyle that's healthy for most people, then tinker intelligently to optimize. If you re-introduce a food and it works for you, great-- you have one less thing to restrict.
Chapter 2 describes the baseline "reset" diet, which is a fairly standard Paleo diet, excluding processed foods as well as grains, dairy, and legumes. Chapters 3-10 explain the basic qualities of a healthy diet, including nutrient density, avoiding "toxic" foods, choosing healthy fat, carbohydrate, and protein foods, choosing natural unrefined foods, and eating nose-to-tail.
There's a lot of good information in these chapters, and none of the complex, "imaginative"** mechanistic arguments that often appear in diet books. I do have a hard time with the liberal use of the word "toxin". I agree that many people benefit from reducing or eliminating gluten (or at least flour-based foods), industrial seed oils, and refined sugar, but it's pretty bold to call them toxic. Many people can probably eat wheat and a moderate amount of refined sugar with impunity, although it's not clear what percentage of the population falls into that category.
Kresser has been, and continues to be, a stalwart defender of the idea that dietary carbohydrate is not inherently unhealthy and can be part of a healthy diet. His recommendations in chapter 6 are consistent with this position, however they recommend a beginning carbohydrate intake between 15 and 30 percent of calories. I'm guessing the rationale for this is that the majority of people will start the diet with weight and/or metabolic issues. Later, the plan allows you to increase carbohydrate intake if it agrees with you and/or if you are highly physically active. I like that he ultimately recommends eating the amount of carbohydrate that works best for you-- not an amount dictated by a rigid theoretical framework.
Chapters 11-17 are my favorite. This is the section that really distinguishes Kresser's book from more canonical Paleo books. It's also the section that has gotten heat from the strict Paleo crowd, because it allows careful departures from the canonical Paleo approach, including the consumption of legumes and dairy. Because of this, some have objected to Kresser's use of the term "Paleo".
As an aside, I used to think I knew what the term "Paleo diet" meant. It means a diet composed of food types that our pre-agricultural ancestors might have eaten, right? So when we learn that humans in the Paleolithic relied heavily on a particular food type, we say "what do we have around the grocery store that resembles that food today-- that's part of the Paleo diet". For example, legumes. There is a large body of evidence that Homo sapiens and even Homo neanderthalensis consumed legumes regularly at a variety of archaeological sites (1), and we know that modern hunter-gatherers continue to consume wild legumes today. Legumes are frequently found at sites of Paleolithic human habitation, they're often cooked, and they're even present in dental plaque (1). Did humans harvest and cook legumes only to use them as mouthwash, or might they have swallowed these calorie-rich seeds? The evidence for wild legume consumption by humans is as strong as it is for any plant food consumed during the Paleolithic. If legumes aren't Paleo, then what is Paleo?
In chapter 11, Kresser describes how to methodically re-introduce foods into your diet to see how you react. I think this kind of empirical approach to designing a diet, when carefully applied, can be very powerful. It addresses the fundamental problem that no single diet is optimal for all individuals. His re-introduction strategy is simple and it doesn't involve any fancy medical tests, but it does tell you how you feel and look when you eat specific foods.
Chapters 12-17 describe Kresser's approach to lifestyle, which includes physical activity, sleep, stress management, pleasure, and social connection. These chapters begin with a "quiz" designed to identify your areas of greatest need. If your score on the quiz is low, it may be an area to focus on.
I particularly enjoyed chapter 12, on cultivating pleasure and connection. Kresser makes the case that we're social animals, and we need frequent, positive social connection to remain healthy and happy. This chapter struck me as wise, and it reminded me of some elements of Mark Sisson's book The Primal Blueprint that I also enjoyed.
The rest of the book describes how to further refine your Personal Paleo Code, including experimentation with macronutrient ratios, building in reasonable departures from the diet, and customizing for specific health problems.
The basic premise of the book is simple and sound: start from a generally healthy diet and lifestyle template, and optimize it to maximize health and well-being and minimize inconvenience. I think it's abundantly clear at this point that no single diet is best for all individuals, and a certain amount of tinkering is necessary to optimize a diet. Kresser brings this concept to the mainstream with a Paleo twist. Your Personal Paleo Code fills an important need and will help many people find their own paths to health.
*I don't think Paleolithic humans were particularly tall. Contemporary hunter-gatherers actually tend to be quite short by modern standards (adult males roughly 5'2" to 5'5"). If there are any archaeologists in the audience who want to confirm or deny this, please do, but the impression I've gotten from my reading is that Paleolithic Homo sapiens skeletons tend to be moderately short by modern standards, with occasional exceptions, consistent with most modern hunter-gatherers and non-industrial agriculturalists. There are some instances of taller individuals from archaic Homo such as Homo heidelbergensis, but most archaic Homo skeletons seem to be on the short side from what I can tell.
** To put it gently.