Low-Carb Diet Research and News

By Janice Billingsley
HealthSCOUT Reporter

SUNDAY, July 30 (HealthSCOUT) -- Forget weight watching. A new study shows that a high-fat diet can help female athletes literally go that extra mile.

Nine women soccer players at the State University of New York (SUNY) at Buffalo went more than one mile farther before reaching exhaustion on a diet of 35 percent fat, says study author, Peter J. Horvath.

"That is really a striking difference," says Horvath, an associate professor at SUNY at Buffalo's School of Health Related Professions.

Women in the study went on three different diets during the second half of three menstrual periods. One month, three women were on a normal diet; another three ate a normal diet plus 415 calories of oil-roasted peanuts a day, and the remainder ate the normal diet plus an equal amount of extra calories from carbohydrate-rich energy bars. Each group switched the following month so that after three months, all had been tested on each of diet.

Each diet was tested for seven days during the luteal phase (the second half) of the menstrual cycle, when a woman's ability to metabolize fat is the greatest, Horvath says.

The peanut diet included 35 percent of calories from fat, compared with 24 percent on the energy-bar diet. The normal diet had 27 percent fat.

The energy-bar diet contained 63 percent carbohydrates, compared to 51 percent on the peanut diet. Protein and calorie intake and caloric expenditure were essentially the same in all three diets.

The endurance tests mimicked soccer play using three running methods: constant-speed, running at different rates on a treadmill and forward running with a side-step maneuver performed on a force plate. The athletes were tested until exhaustion on the seventh day of each diet.

The results showed that team members traveled 11.2 kilometers on the high-fat diet, 10 kilometers on the normal diet and 9.7 kilometers on the high-carbohydrate diet. Muscle performance, measured by the force plate, remained the same.

Columbia University's women's soccer coach Kevin McCarthy says the study's findings, originally presented at an annual meeting of the Federation of American Societies of Experimental Biology, could be helpful.

"Outside of planning a lot of meals during the season, we stick to having [our players] eat well and get the proper mix of carbohydrates and fats. [This information] isn't dangerous or a fad. It's an easy thing to pass along to players," McCarthy says.

Horvath says a high-fat diet seems to be more of a boost to women than to men, based on previous studies he has done with male athletes.

"Men responded to calories, but women responded to fat," he says.

As a result of his findings, he says, "Any research that had been done on men has to be redone for females. Dietary recommendations for women athletes should be different from men's."

"An athletically fit woman's fat intake in her diet should be about 25 percent," says St. Louis dietician and personal trainer Ellie Zografakis. But she says there is no harm in higher fat intake for athletes because endurance exercise is a very efficient use of fat.

"With a diet of 35 percent fat fuel, [the athletes] would have more energy, feel more powerful," she says. However, she warns against increasing the fat intake by lowering the carbohydrate intake too much. An intake below 50 percent would be inadequate for performance, she says.

Zografakis says, in fact, most of her clients don't get enough fat; only 10 to 20 percent of their calories come from fat, which she says is too low.

"Fat is taboo for all women. They are not willing to increase their fat intake," she says.

Instead, she says many women have a high carbohydrate intake -- as much as 80 percent of their diet -- which can cause bloating along with a lack of energy.

What To Do

Tufts University rates a number of commercial sites that offer nutrition advice for athletes.

For general information about fat in diets, see the Heart Information Network.