Review from Health Magazine
Sears may say his
diet doesn’t require a “great deal of unrealistic self-sacrifice,” but the whole notion of achieving a precise balance of protein and carbs at each meal could be one big headache for many folks. Calorie counting it ain’t, yet you need a keen knowledge of portion sizes and nutrient profiles to keep in the Zone—and that’s going to take a lot of work. Another big problem: The whole strategy is based on a shaky scientific foundation.
There’s no proof that food puts dieters in the Zone or that being there promotes
weight loss. It’s probably the
diet’s low calorie level that peels off the
pounds.
Does the diet take and keep weight off?
No more or less than many other popular plans. At least that’s the word from researchers at Tufts–New England Medical Center in Boston who randomly assigned 160 overweight volunteers to one of four weight-loss regimens:
Atkins, Dean Ornish, Weight Watchers, and The Zone. After one year, average
weight loss among participants was a modest 5 percent regardless of the program. Sears presents his own findings, however. In a 6-week study of 91 slightly overweight volunteers, women who followed the
diet lost an average of 7
pounds of
fat, and their overall
body-
fat percentage dropped from 29 percent to 26 percent. Men lost an average of 3
pounds of
fat and dropped from 20 percent to 17 percent
body fat.
Is the diet healthy?
It’s not certain. The fact that the Zone promotes monounsaturated fats like olive oil, olives, and peanuts, as well as the omega-3 fats found in fish oils, is good. And 30 percent of
calories from
fat is a moderate, realistic approach that the federal government and health organizations like the American Heart Association have long promoted. The unclear part: 30 percent protein is a little higher than most health organizations recommend. And 40 percent carbs is a little lower than advisable. Without long-term data on the health effects of low-carb, high-protein diets, there’s no absolute guarantee of safety.
What do the experts say?
Registered dietitian Pat Kendall, PhD, a food scientist and human-
nutrition specialist with Colorado State University’s Cooperative Extension, thinks the Zone is a mixed bag. “It promotes eating regular meals, which is good,” Kendall says. “And it’s low enough in
calories to promote
weight loss. But it’s too low in
calories to serve as a long-term
diet regimen.” She finds it alarming that Sears eats only 1,332
calories per day to stay in the Zone. “Thirteen hundred
calories is considered a low-calorie
diet even for a small woman,” Kendall says. “It’s a very low-calorie
diet for Sears, who clocks in at 6 feet 5 inches tall and weighs 210
pounds.” What about the whole hormone-Zone philosophy? Unproven. Like a lot of the low-carb diets, the Zone relies on “poorly controlled, non-peer-reviewed studies, anecdotes, and nonscience rhetoric,” reports Samuel N. Cheuvront, PhD, RD, of the U.S. Army Research Institute of Environmental Medicine in Natick, Massachusetts. Cheuvront, who just published an in-depth review of the Zone for the Journal of the American College of
Nutrition, concludes that the protein-carb ratio the
diet supports has no basis in scientific fact and that Sears “selectively ignore[s] the known effects of macronutrients and hormones that contradict the Zone theory.” In other words, there are a lot of holes in Sears’ philosophy.
Who should consider the diet?
Number crunchers might get a kick out of keeping such close tabs on protein and carbs. The
diet is not recommended for people with kidney problems; a large amount of protein in the
diet can overtax kidneys.
Bottom line: Even though the Zone philosophy may be more rhetoric than scientific fact, the plan has some good points. It offers a healthy approach to
fat. It’s also laudable that Sears emphasizes lean proteins and encourages plenty of fruits and vegetables. It’s just too little food once you’ve shed the
pounds. After reaching their weight-loss goals, dieters need to increase portions slightly.
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