Zone Diet: Everything You Need to Know and Probably More
Diets come and go, but one that’s stuck around for a few decades is the Zone Diet . Its founder calls it “a calorie-restricted diet that is protein-adequate, carbohydrate-moderate, and low in fat,” and won’t lead to hunger or fatigue. The Zone Diet also claims to be able to lower inflammation in the body and prevent blood sugar spikes.
But is the Zone Diet safe? Is it effective? And is it easy to follow for the long haul? Before you get into the zone, read up on the Zone Diet plan — and find out what the science has to say.
What Is the Zone Diet?
The Zone Diet is a low-carbohydrate diet that “aims to reduce inflammation in the body by thinking of food as ‘medicine’ and encouraging people to eat the right foods to stay in ‘the zone,'” says Natalie Allen, MS, RD, an instructor of biomedical sciences at Missouri State University.
It’s been around since the 1990s — yes, the very decade that brought us Friends, the fat-free food fad, and boy bands. Designed by biochemist Dr. Barry Sears, it was a New York Times best-seller that had a lot of famous followers, including Jennifer Aniston, Sandra Bullock, and Demi Moore.
The Zone Diet shouldn’t be confused with a Blue Zone “diet”, which mimics the menus customary in parts of the world where people regularly live long enough to celebrate their 100th birthdays. And it also shouldn’t be mistaken for that other popular low-carb diet from the ’90s, the Atkins Diet.
How Does the Zone Diet Work?
The Zone Diet recommends a balance of 40 percent carbs, 30 percent protein, and 30 percent fat. It’s also rather low in calories, recommending 1,200 a day for women and about 1,500 for men, divided into three meals and two snacks. (All of which must maintain the 40/30/30 breakdown; no loading up on protein at breakfast to feast on carbs at lunch.)
“An important key to this diet is to eat frequently and not let blood sugars dip too low,” explains Allen. “The recommendations are to eat, at minimum, every five hours. By eating fewer carbs and consuming the zone combination of foods each time, the goal is to regulate insulin production by the body.”
The Zone Diet also uses three clinical markers (measured by blood tests) to see if you’re “in the zone.” Those markers indicate:
- Your level of insulin resistance in the liver.
- Your body’s level of diet-induced inflammation.
- Your blood glucose levels.
If you get out of “the zone,” the diet’s creator says, “you gain weight, you develop chronic disease at an earlier age, and you age at a faster rate.”
Sound complicated? It can be. There are actually two ways to follow the Zone Diet: One involves using your hand and your eyes. The other is more involved and could involve using a Zone Diet calculator, Zone Diet meal plan, and even Zone Diet-approved nutrition bars.
Easy: Hand, eye, watch method
To keep the Zone Diet simple, you only need your hand, your eyes, and a watch. (Or, in 2019, a smartphone, but those didn’t exist when the diet was invented.)
- When preparing a meal or snack, measure a portion of low-fat protein roughly the size of your hand.
- Use your eyes to estimate what’s on your plate. A third of your plate should be protein and the other two-thirds should be low glycemic carbs (i.e. vegetables), with a small amount of healthy fat (think a drizzle of olive oil).
- Use your watch/phone to remember to eat every five hours (at least). Your five fingers are also supposed to remind you of this rule.
Precise: Zone Diet blocks
If that’s not exacting enough for you, Zone Diet blocks allow you to customize your daily intake. First you need to use a Zone Diet calculator, entering your height, weight, some measurements, and your activity level. The Zone Diet then assigns you a custom number of “blocks” per day and meal.
- A protein block equals 7 grams of protein.
- A carb block equals 9 grams of carbohydrates (net carbs, or carbs minus fiber).
- A fat block equals 3 grams of fat.
- One of each macronutrient block equals a Zone block.
- Snacks equal one Zone block, while meals total three to five.
What Can You Eat on the Zone Diet?
Unlike some other diets, the Zone Diet includes a wide range of foods, but it does have rules. “Dieters are encouraged to think of starches, such as noodles and bread, as condiments, not main dishes,” explains Allen.
“Foods with a high glycemic index are also limited. Healthy foods are the base of the diet and most fall into categories a dietitian would recommend. For example, chicken stir fry with veggies (no rice), a turkey burger, or an egg white omelet with veggies.” High glycemic index foods are foods that cause your blood sugar to spike, which is exactly what the Zone diet is looking to avoid.
Here are some of the foods you’re encouraged to eat on the Zone Diet.
Low-fat proteins are preferred.
- Egg whites
- Fish and shellfish
- Lean beef
- Low-fat cheese
- Low-fat cottage cheese
- Protein powder
- Skinless chicken or turkey breast
- Tofu and other soy products
- Turkey bacon
Choose carbs with a lower glycemic index.
- Fruits, including apples, oranges, berries, and stone fruit
- Whole grains like oats and barley
- Vegetables, including cucumbers, mushrooms, peppers, dark leafy greens, onions, squash, legumes, broccoli, and cauliflower
Monounsaturated fats are encouraged.
- Canola oil
- Nut butters
- Nuts and seeds
- Olive oil
List of Foods to Limit on the Zone Diet
You can eat almost anything on the Zone Diet, as long as you’re “in the zone.” A few foods are discouraged.
- Egg yolks
- Fatty cuts of meat
- Higher-sugar fruit like raisins and bananas
- Refined starches and grains, such as white bread and pasta
- Added sugar in food and beverages
- Starchy vegetables like potatoes and corn
Stated Benefits of the Zone Diet
Before you decide whether to give it a try, consider the purported pros and cons of the Zone Diet. We’ll start with the benefits championed by its proponents.
“Eating protein at each meal will promote satiety, but the ratio of protein to carbs may be confusing for some to calculate,” says Allen. “Eating frequent meals and pairing protein, fat, and carbs in foods is a good idea for blood sugar control.”
Impact on weight loss
“Studies on the Zone Diet show that people lose some weight, but it can be hard to maintain,” says Allen. A 2007 comparison of the Zone Diet to three other diets (Ornish, LEARN, and Atkins) found that Zone Dieters lost about as much weight (6 pounds) after two months as the LEARN and Ornish dieters, though not as much as the Atkins dieters (9 ½ pounds). But after a year, the Zone Diet group had only kept off about 3 ½ pounds — less than all of the other groups.
Effect on blood sugar
Research published in 2015 in the Journal of the American College of Nutrition found that the Zone Diet did reduce inflammation and waist size, and improved glycemic control in patients with type 2 diabetes in “real-life situations.”
Arguments Against the Zone Diet
While most of the Zone Diet’s recommendations seem reasonable, there are some caveats to consider before you start blocking out your meals.
It might be hard to follow long term
While the Zone Diet might be fine for a couple of weeks or a month, it may be complicated when followed as a lifestyle. Allen’s advice?
“When looking at any diet plan, ask yourself: ‘Is this sustainable? Can my whole family eat this way? How much work and meal prep are going to be needed?’ Then, choose the plan that is right for you.”
It’s not designed for athletes
A criticism published in the journal Sports Medicine shortly after the book was published was adamant that the Zone Diet would impair rather than improve athletic performancedue to its low-carb format and calorie restrictiveness. “Athletes, children, and pregnant women do not need to limit carbs to this degree,” says Allen.