The zone diet is a high-fat, low carbohydrate diet based on a very specific macronutrient break down and a recommendation of low-glycemic foods.
Specifically, the macronutrient break down is to consume 30% dietary protein, 40% dietary carbohydrates, and 30% dietary fat.
It is typically prescribed in “blocks” and to eat around 5 meals per day.
Some of the key tenets of the diet are consuming mostly low insulin releasing foods, optimizing satiety, and specific nutrient timing: 5 meals per day with no more than 5 hours between meals.
HISTORY OF THE ZONE DIET
The zone diet was developed by Dr. Barry Sears, a biochemist by training.
Tracing back in history the zone diet truly began in the 1970s when Dr. Sears was completing his postdoctoral fellowship and his father died of a heart attack.
This life changing event spurred Dr. Sears to research the causes of heart disease and he began to develop a theory about how dietary fat and how it regulates the body’s chemistry and hormones are key players in the development of obesity and disease.
GENERAL OVERVIEW OF COMPONENTS & MAIN PRINCIPLES OF THE ZONE DIET
The underlying idea behind the zone diet is the idea that insulin and other hormones causes inflammation, and that inflammation is the key to obesity and heart disease. The structure of the entire diet is designed to minimize these two things by optimizing hormones.
The zone diet prescribes consuming a 0.75 or 3:4 ratio of protein to carbohydrate in order to reduce the insulin to glucagon ratio1. The idea is that consuming this ratio optimizes the production and regulation of eicosanoid metabolism and reduces disease risk, augments weight loss, and make you live longer.
Applying the diet requires calculating the amount of blocks you need to consume in a day. Each person is allotted a total number of blocks throughout the day. The amount each person is allowed is based primarily on biological sex, overall size, and athletic status.
The total amount of blocks often range from 10 total daily blocks for a small female, all the way to 25 for an athletic - well muscled male. Meals are then broken down in to 5 meals per day with blocks distributed across each meal.
Blocks are broken down by each macronutrient: 1 protein block is 7 grams of protein, 1 carbohydrate block is 9 grams of carbohydrates, 1 fat block is 1.5 grams of fat. Each meal should include an equal number of each block. For example, a 2 block meal will have 2 protein blocks, 2 carbohydrate blocks, and 2 fat blocks.
The following figure gives a graphical overview of a typical zone diet breakdown.
The zone diet prescribes a rigid number of meals and fairly rigid time structures.
The mantra of the zone diet is “5 Meals per Day, No More than 5 Hours Apart”.
The zone diet has a specific food list that zone diet practitioners are encouraged to follow as closely as possible. Here is a list of foods that are encouraged by the zone diet.
Proteins: Range Fed Beef, Chicken, Turkey, Bass, Halibut, Lobster, Shrimp, Egg Whites
Fat: Almonds, Avocado, Macadamia Nuts, Olive Oil, Peanuts, Tahini, Cashews, Pistachio, Sesame Oil
Carbohydrates: Asparagus, Black Beans, Broccoli, Cabbage, Cauliflower, Chickpeas, Kale, Lentils, Squash, Zucchini, Apples, Berries, Grapes, Oranges, Peaches. Slow digesting grains like Barley and Oatmeal are also allowed.
Does it include phases?
Typically the zone diet does not include prescribed phases in either its original formulation or the most recent update.
Who is it best suited for?
The zone diet is best suited for individuals who are concerned with developing a dietary framework that focuses on both the quantity and quality of their diet and enjoy a structured, planned out diet.
The blocks specify the quantity of an individual’s intake and the timing and dispersal of the blocks gives structure to a day of eating; this is often a benefit for many. The list of foods focuses on the quality of the diet.
How easy is it to follow?
The zone diet often has a steep learning curve as individuals adopting the zone diet are required to learn about macronutrients, blocks, and a food list. Calculating blocks often requires weighing and measuring food which can also be a steep learning curve.
However, the zone diet can be easy to maintain once the baseline skills and patterns are establish. The restrictive nature of the food list is perhaps the biggest barrier to long term adherence.
Mainstream belief behind diet
The mainstream belief behind the zone diet is that a specific ratio of macronutrient intake, and certain foods can optimize insulin and other hormones to maximize health, longevity, and weight loss.
Scientific Studies and Interpretation of Data
A few studies come to mind when discussing the benefits of implementing the zone diet into your lifestyle.
Some showcase that several intervention studies have had positive affects for fat loss when the diet was adhered to.
Others indicate that the zone diet can have a positive influence on several health parameters.
The zone diet has been extensively studied in the medical literature from a weight loss prospective. It has been well established over dozens of intervention studies that the zone diet can and does induced both weight loss and fat loss2-5.
When compared to other popular weight loss and fat loss diets, the zone diet appears to convey very similar fat loss potential, making it a very viable fat loss option for many people.
While the zone diet is often used as a fat loss tool, it was originally created to improve health markers. When followed as prescribed and typically in a hypocaloric diet, weight loss setting, the zone diet can improve several markers of health parameters.
For example, in one study, the zone diet showed that it improved body weight, glycemic control, waist circumference, and inflammatory markers in individuals with type 2 diabetes6.
The zone diet is a dietary framework that utilizes a 30/40/30 ratio of protein, carbs, and fat intake with the aim of optimizing hormonal signaling.
The diet focuses on vegetables, some fruits, and other non-starchy carbs and typically utilizes a lower-carbohydrate, higher fat intake.
One of the main philosophies is consuming low insulin releasing foods, optimizing satiety, and specific nutrient timing by consuming 5 meals per day with no more than 5 hours between meals.
- The Zone Diet phenomenon: a closer look at the science behind the claims.
- Alternatives for macronutrient intake and chronic disease: a comparison of the OmniHeart diets with popular diets and with dietary recommendations.
- Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial.
- Blood profiles, body fat and mood state in healthy subjects on different diets supplemented with Omega-3 polyunsaturated fatty acids.
- Comparison of high-fat and high-protein diets with a high-carbohydrate diet in insulin-resistant obese women.
- The ZONE Diet and Metabolic Control in Type 2 Diabetes.