University professor supports Zone diet
Zak Stambor
Contributing writer
A University professor thinks the best means of losing weight, maintaining muscle mass and decreasing body fat might be with the Zone Diet.
University nutrition professor Donald Layman discussed results of a Zone Diet study he conducted, in the February issue of the Journal of Nutrition.
The percentage of Americans classified as overweight or obese has steadily grown to nearly 64 percent, according to the National Health and Nutrition Examination Survey.
To counter this trend, nutrition experts have been debating the ideal combination of protein, carbohydrates and fats that people should consume.
Unlike popular trend diets that tend to focus on extremely high-protein levels like the Atkins’ Plan or low-protein levels like the Ornish Plan, the Zone Diet falls within the protein range recommended by the National Academy of Science’s Food and Nutrition Board.
The Zone is “the metabolic state in which the body works at peak efficiency,” according to the diet’s founder Barry Sears in The Zone: A Dietary Roadmap to Losing Weight Permanently.
The zone is achieved by maintaining a diet that is 30 percent fat, 30 percent protein and 40 percent carbohydrates.
Layman’s findings focused upon the Zone Diet’s increase in the consumption of high quality protein which, in turn, leads to an increase in leucine — an amino acid responsible for the regulation of muscle.
“By targeting fat rather than muscle, dieters lose weight more effectively,” Layman said. “Maintaining muscle mass helps the body burn more calories.”
While the body produces many amino acids, it does not produce leucine. The Zone, therefore, relies on the consumption of foods with high concentrations of the amino acid, such as beef, dairy products, poultry, fish and eggs, Layman said.
Subjects in Layman’s study were 24 middle-aged, overweight women who consumed 1,700 calories a day for 10 weeks. The subjects increased their protein consumption to about .73 grams of protein a day and reduced their daily intake of carbohydrates to .95 grams a pound of body weight.
The control group ate according to the USDA Food Guide Pyramid, consuming about .36 grams of protein and 1.3 grams of carbohydrates per pound of body weight a day, Layman said.
“Developing the menu for the subjects was fairly difficult,” said James Painter, developer of the study’s menus. “In order to maintain the 30-30-40 macronutrient ratio, we had to rely heavily on foods such as fish and fowl that are naturally low in fat.”
Subjects in both diet groups lost an average of 16 pounds each; however, those who followed the Zone diet lost more body fat and less muscle mass than the control group, Layman said.
“We’ve been trained to believe that there’s one healthy diet model,” Layman said. “Yet in reality there is more of a range of diet plans that will work — this plan provides people with another viable alternative.”
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