Providence, RI –A recent study suggests that the fat intake of successful weight losers entering the National Weight Control Registry has increased over the past decade, while carbohydrate intake has declined. This is the finding of a research paper appearing in the April 2006 issue of Obesity Research by researchers at The Miriam Hospital and Brown Medical School, and University of Colorado.
The National Weight Control Registry is a national study tracking individuals who have lost at least 30 pounds and kept if off for at least one year. On average, the nearly 5,000 members in the Registry have far exceeded these requirements, losing over 70 pounds and keeping the weight off for nearly six years.
"Our findings suggest that to successfully maintain weight loss, dieters may be able to vary their diet over time," says Suzanne Phelan, PhD, lead author of the study, staff psychologist at The Miriam Hospital and assistant professor at Brown Medical School. "When the National Weight Control Registry was created 10 years ago, members reported consuming a low-calorie, very low-fat diet and engaging in high levels of physical activity to maintain weight loss - what we wanted to determine in this study is whether the eating and exercise habits of participants enrolling in the Registry had changed over the past decade."
Researchers studied the dieting behaviors of the more than 2700 individuals who enrolled in the National Weight Control Registry during the years 1995 to 2003. Evaluations of diet and physical activity were conducted as participants entered the Registry and were monitored over intermittent periods of one year.
"We found that participants who enrolled in the Registry in more recent years, reported consuming an increased number of calories from fat, and fewer carbohydrates compared to those who enrolled in 1995," says Phelan.
From 1995 to 2003 - the daily percentage of calories consumed from fat increased from 23.8 percent to 29.4 percent, while calories from carbohydrates decreased from 56 percent to 49.3 percent. In addition, saturated fat intake in Registry participants increased from 12.3 grams per day to 16.6 grams per day in later years.
"Despite the increase in fat intake, the consumption of fat that the participants reported in later years continued to remain within recommended levels and well below the national average," explains Phelan. "However, potentially more troubling is the increase in saturated fat intake – the type most closely linked to an increase in heart disease."
Low carbohydrate dieters, characterized by those who consume less than 90 grams of carbohydrates per day, remain a minority of the Registry's participants, but did increase from 5.9 percent to 17.1 percent from 1995 to 2003.
Phelan cites that the rise in popularity of the low carbohydrate diets might explain, in part, the shift in more recent years to participants consuming consistently lower amounts of carbohydrates.
Despite fluctuations in participant's fat and carbohydrate consumption over the years, physical activity levels remained high with participants averaging 60 minutes of moderate exercise per day. Moreover, the characteristics associated with continued weight loss maintenance one year later remained the same.
"In the sample as a whole – Registry members who maintained a low-calorie diet with moderate fat intake, limited their fast food consumption, and sustained high levels of physical activity, reported continued success in weight loss maintenance one year later," says co-author Rena Wing, PhD, co-founder of the National Weight Control Registry and director of the Weight Control and Diabetes Research Center at The Miriam Hospital and Brown Medical School.
The authors write that even though more than 75 percent of the National Weight Control Registry's members report consuming a diet that is at or below recommended levels of fat intake - these findings indicate that it may be possible to maintain a reduced body weight through various dietary approaches.
James O. Hill, PhD, and Holly R. Wyatt, MD, from the University of Colorado Health Sciences Center also participated in the study.
The researchers are continuing to study successful weight losers and are currently recruiting for a national study, Living Lean in a Toxic Environment (LITE), which investigates whether normal weight individuals without a history of obesity maintain their body weight in a similar fashion to normal weight long-term successful weight losers. Participants will wear a small device that measures physical activity, while food consumption information will be collected through telephone interviews by research staff. Monetary compensation and personalized feedback about diet and activity are provided. For additional information about the LITE study, call 1-877-371-LITE (5483).
The Miriam Hospital, established in 1926 in Providence, RI, is a not-for-profit hospital affiliated with Brown Medical School. Nationally recognized as a top hospital in cardiovascular care, The Miriam Hospital (www.miriamhospital.org) offers particular expertise in cardiac catheterization, angioplasty and women's cardiac care. One of 20 designated Center for AIDS Research (CFAR) sites, The Miriam is a leader in the treatment, research and prevention of HIV/AIDS, attracting $17 million of the world's HIV/AIDS research dollars. The Miriam Hospital has been awarded Magnet Recognition for Excellence in Nursing Services three times and is committed to excellence in patient care, research and medical education. The Miriam is a founding member of the Lifespan health system.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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