A Note From the Authors
When we wrote the original Renaissance Diet, it was the first comprehensive description of our diet approach based on the most up-to-date nutritional data available and on our experience with hundreds of clients. Our original book was one of the first to synthesize the current literature on nutrition for body composition and performance and to present it in an ordered, logical, and understandable manner. This early version of the Renaissance Diet was also the first to identify the most important factors for successful dieting and delineate their practical application.
It has been a few years since the original Renaissance Diet was published, and two major things have changed since then: First, the interim years of scientific research have increased and refined our knowledge of how to lose fat, gain muscle, and improve performance. Second, through a combination of one-on-one coaching and digital products, Renaissance Periodization has now helped several hundred thousand people with their diets. These people range from those just trying to get in shape for the first time to world champion athletes. This collective coaching experience has refined our strategies and tactics with respect to the application of all our scientific knowledge. The summation of all this data and experience is now available to you, right here in this book.
This newest version of the Renaissance Diet is not only updated and refined, but also expanded. Special diet considerations and information on female-specific diet issues have been added along with information on gut health and an extensive section debunking some of the current and pervasive diet fads and fallacies. We put a great deal of effort into making this book bigger and better so that you can use it to become bigger, better, faster, stronger, leaner–whatever your goals call for.
We did this because we hate pseudoscience, scams, and quacks. We did it because we want to give you, our readers, our clients, and our friends in science, the best, most up-to-date information so that you can change your body, your performance, and your health for the better.
We sincerely hope you enjoy this book and will put the knowledge you gain from it to use in reaching your health and fitness goals.
Dr. Mike Israetel
Dr. Melissa Davis
Dr. Jen Case
Dr. James Hoffmann
PART I
NUTRITION PRINCIPLES AND PRIORITIES
CHAPTER 1
The Diet Priorities
There are countless diet options available these days. If you would like some evidence to back this statement, try looking up “fat loss diet.” New diets that promise to help you lose fat, build muscle, and increase performance pop up online nearly every day. Some diets eliminate entire food groups while others focus on consuming solely those same food groups. In reality, the science of dieting has moved beyond the scope of just controlling food groups; you have likely heard of concepts such as macronutrients, total calorie intake, and meal timing. The scientific basis and reasoning behind the various available dietary regimens are not often made entirely clear. With so many opposing options, just deciding how to diet can be a frustrating and seemingly hopeless endeavor.
The good news is that there are five main principles, along with adherence to those principles, that contribute to any diet’s effectiveness. Differences in implementing these principles account for all variations between diets and their outcomes. We can get lost in the superficial aspects of the many diet options available. One diet may require you to eliminate carbohydrates from your meals, whereas another calls for fasting. The intended outcome of each of these is generally weight loss. What might jump out at you is the lack of carbs or the fasting periods, but these are just superficial aspects–both these diet alterations are meant to achieve one goal: a calorie deficit. It is the calorie deficit that results in the weight loss, not the lack of carbs or meal timing.
Calorie balance is the first and most important of the diet principles, and any diet that works well will manipulate calories directly or indirectly. The other four diet principles can also alter superficial aspects of a diet. Once you have learned to see past these superficial aspects and identify each of the five underlying diet principles, you will be able to assess their roles and predict that diet’s effectiveness.
Diets vary quantitatively across one or more of the following five principles:
1.Calorie Balance: How many calories you eat per day relative to how many you burn.
2.Macronutrient Amounts: How many grams of protein, carbohydrate, and fat you eat per day.
3.Nutrient Timing: When and how you spread your total food intake across daily meals.
4.Food Composition: The sources of macronutrients you consume.
5.Supplement Use and Hydration: How much and what type (if any) dietary supplements you consume and your level of hydration.
All these factors contribute to rates of weight loss or weight gain as well as differences in athletic performance. As we will learn, some of these principles are more powerful than others in determining outcome.
Although adherence is not a programmed aspect of a diet, it is critical. If the diet were a race car, adherence would be the driver; without a driver, the car does not race. A good driver can get the best possible performance with any given machine, but a bad driver can crash even the best car. Simply put, you cannot succeed on a diet you do not follow, regardless of how good the diet is.
When we wrote the first edition of this book some years ago, we took an extensive look at the research on dieting for fitness. We assessed effect sizes, which are measurements of how much change in outcome is observed when a specific variable differs between groups. Studies that varied calorie balance alone showed the most significant effects; studies that manipulated macronutrient intake (without altering calories) showed smaller but still significant differences in body composition changes. Altering nutrient timing (without changes to calories or macronutrients) resulted in very small differences in outcome. The effect of changes in food composition or supplement use on fitness outcomes was undetectable in most cases. As a testament to the fact that adherence to any diet is a prerequisite for its success, metabolic ward studies, in which subjects do not leave the research facility and can only eat the food administered by researchers, are the gold standard in nutrition research because of the near perfect adherence that results from these conditions.
We qualitatively consolidated data from these investigations and came up with estimated relative effect sizes for the five principles of dieting:
Calorie Balance: approximately 50%
Macronutrient Amounts: approximately 30%
Nutrient Timing: approximately 10%
Food Composition: approximately 5%
Supplements and Hydration: approximately 5%
Again, these percentages only apply to the extent that an individual adheres to a given diet. A perfectly planned calorie balance, for example, will not have the desired effect if the dieter is not eating those planned calories.
Figure