Water-Rich Diet More Effective Than Low-Fat Regimen for Weight Loss

Jane Salodof MacNeil

November 18, 2004

Nov. 18, 2004 (Las Vegas) — Obese women encouraged to eat water-rich foods lost significantly more weight than counterparts who were told to eat less fat in a randomized controlled trial of two approaches to dieting.

The women in the first group were in a program based on reducing the energy density of what they ate. By the six-month mark they had lost 9.4 kg. The control group also lost weight — but not as much: 6.7 kg at that point.

"Incorporating low-energy-dense foods into a diet was more effective for weight loss than reducing fat alone," said investigator Julia Ello-Martin, a doctoral candidate from Pennsylvania State University in University Park. She reported outcomes here yesterday at the annual scientific meeting of the National Association for the Study of Obesity.

The 12-month trial enrolled 101 obese women in their mid-40s with body mass index (BMI) scores between 30 and 40 kg/m 2. All participants received individual counseling, but neither the energy-density cohort nor the reduced-fat cohort was given a specific regimen to follow.

Instead, the experiment plied the energy-density group with positive messages, according to Ms. Ello-Martin. The women were encouraged to eat fruits, vegetables, legumes, whole grains, soups, and high-fiber and reduced-fat foods. Portion size was not an issue.

In contrast, the reduced-fat group was counseled to limit portions and eat less fat. Although this cohort also lost weight, Ms. Ello-Martin said the energy-density group pulled ahead by the fourth month.

Six-month data show that both groups consumed about 28% of daily energy from fat. Average energy density of the foods consumed was less for the energy-density group, however: 1.18 kcal/g vs 1.44 kcal/g. This more successful cohort also ate significantly more fruits and vegetables: 5.1 vs 3.5 servings per day.

One argument for the energy-density approach is that dieters can eat larger portions without increasing calories. "Women in the energy-density group were able to consume a significantly greater amount of food than women in the reduced fat group," Ms. Ello-Martin said. Consequently, she suggested they were less likely to feel hungry.

The analysis was based only on women who completed the program — 33 in the energy-density group and 36 in the reduced-fat group. About 29% of participants withdrew from the trial, according to Ms. Ello-Martin.

The National Institutes of Health supported this study.

Session chair Holly Wyatt, MD, from the University of Colorado in Denver, said the energy-density diet is another approach to getting people to consume fewer calories. Some people may be more successful because they can eat a larger volume of food for the same amount of calories, she said.

NAASO 2004 Annual Scientific Meeting: Abstract 90-OR. Presented Nov. 17, 2004.

Reviewed by Charlotte E. Grayson, MD


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