Star ratings reflect scores of 1 to 5 assigned to the Zone diet in seven categories by nutritionists, specialists in diabetes and heart disease, and other diet experts on a ratings panel assembled by U.S. News. (See our Best Diets methodology.) Overall, Zone landed in the lower middle of our ranked diets. While it provides decent nutrition and is relatively safe, experts gave it mediocre scores in nearly all measures, including weight loss, how easy it is to follow, and effect on diabetes and heart health. The diet is “balanced in terms of nutrition, but the evidence behind it seems rather weak,” according to one expert. Below, ratings in all categories and how the experts’ opinions broke down.
Short-Term Weight Loss
Experts were lukewarm on short-term weight loss. While Zone dieters have a reasonable shot at losing a significant amount of weight during the first year, experts felt weight loss is likely due to significant calorie restriction, not the balanced proportion of nutrients that the diet claims is key.
Long-Term Weight Loss
Don’t expect to keep pounds off for the long haul, according to experts; the Zone diet scored poorly on long-term weight loss. It’s “not sustainable for most people,” one expert said, since involves a low ceiling of daily calories and tedious meal preparation.
Easy to Follow
The Zone diet performed poorly, a reflection of the laborious care required to eat the right proportion of the right foods at every meal. (Your plate must always contain 40 percent carbs, 30 percent protein, and 30 percent fat.) “Because of the ratios of nutrients that this diet is based on, it almost takes an engineer to follow it—or a mathematician,” one expert said.
The Zone diet pulled a slightly higher score in the nutrition category than it did in most others, but it still doesn’t meet all the government recommendations. You won’t get enough carbs, and you may have trouble obtaining the appropriate amounts of fiber, potassium, calcium, and vitamin D.
Experts judged the Zone diet’s safety to be its best attribute, but many other diets were even safer. Though no indications of serious side effects have surfaced, check with your doctor to make sure the Zone diet is right for you.
Zone received discouraging reviews as a diet for diabetes, beating out only two other diets in this category. No good evidence suggests it helps prevent or control the chronic disease.
For Heart Health
The Zone diet didn’t impress as a heart-healthy diet, and it lagged behind most other diets on this measure. Experts gave it a middling score shy of 3 stars out of 5.
Last updated by Angela Haupt | January 02, 2013
The low-carb Atkins diet leaves much to be desired. It's effective for short-term weight loss, but isn't great for overall health.
Nutrisystem determines portions, prepares and delivers your meals, and tells you what to eat and when.
On this diet, eat 5 Medifast products each day and one self-prepared meal. Medifast aids short-term weight loss, but isn't sustainable enough to last.