People who are obese or severely obese can lose a considerable amount of weight if they receive a structured one-year weight loss program combined with physical activity, according to two reports published in the Journal of the American Medical Association (JAMA). A person is considered as obese when their Body Mass Index (BMI) is 30 or above. A BMI of between 20 and 25 is seen as ideal, while between 25 and 29.9 is overweight.
The authors explain that obesity rates in the USA have been rising steadily for the last thirty years - it has become one of the major public health problems of this century, particularly among African-American females.
According to the one of the reports, 68% of adults in the USA have a BMI of 25 or more, meaning that over two-thirds of the country's adult population is either overweight or obese. Being overweight or obese significantly increases the risk of developing diabetes and hypertension (high blood pressure).
Bret H. Goodpaster, Ph.D., the University of Pittsburgh School of Medicine and team assessed a lifestyle intervention study which included a combination of structured diet and physical activity. The 1-year study involved 130 severely obese adult participants. None of them had diabetes. They were randomly selected into two groups and were monitored for weight loss for 12 months.
- Group 1 - the combined diet and physical activity group. During the whole twelve-month period their program consisted of a structured diet plus physical activity.
- Group 2 - delayed physical activity group. This group had the same program as the one above, however, their physical activity did not begin until six months into the program.
To facilitate dietary compliance and improve weight loss, liquid and pre-packaged meal replacements were provided at no cost for all but one meal per day during months one through three and for only one meal replacement per day during months four through six of the intervention.
Physical activity - each individual was given a pedometer, a device which measures how many steps you take. They were asked to try to walk 10,000+ steps daily. They also had to do a 60-minute brisk walk each day. There were some small financial incentives for those who managed to do this.
The lifestyle intervention included group, individual and telephone sessions.
The authors wrote:
Of 130 participants randomized, 101 (78 percent) completed the 12-month follow-up assessments.
The Diet and Physical Activity Group (Group 1) lost 24 pounds during the first six months, compared to 18 pounds loss in the other group (Group 2). At the end of the 12-month period Group 1 lost an average of 27 pounds, compared to 22 pounds in Group 2.
The researchers added and then concluded:
Waist circumference, visceral abdominal fat, hepatic (liver) fat content, blood pressure and insulin resistance were all reduced in both groups.
In conclusion, intensive lifestyle interventions using a behavior-based approach can result in clinically significant and meaningful weight loss and improvements in cardiometabolic risk factors in severely obese persons. It is also clear that physical activity should be incorporated early in any dietary restriction approach to induce weight loss and to reduce hepatic steatosis [fatty liver] and abdominal fat. Our data make a strong case that serious consideration should be given by health care systems to incorporating more intensive lifestyle interventions similar to those used in our study. Additional studies are clearly needed to determine long-term efficacy and cost-effectiveness of such approaches.
Donna H. Ryan, M.D. and Robert Kushner M.D., M.S. wrote in an accompanying Editorial:
"Class II obesity (body mass index [BMI] of more than 35) and class III obesity (BMI of 40 or more) is a prevalent condition that adversely affects health," according to Donna H. Ryan, M.D. of Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, and Robert Kushner, M.D., M.S., of Northwestern University Feinberg School of Medicine, Chicago, in an accompanying editorial.
Severe obesity is a prevalent public health problem, disproportionately affecting women and minorities. There is still much to learn about the mechanisms underlying differing risk and treatment outcomes between populations. Optimal treatment approaches for class II and class III obesity are underexplored, while payment approaches for interventions known to work have yet to be adopted.
Additional rigorous research, such as the clinical trial by Goodpaster et al, are needed to unravel the causes, identify prevention strategies, and develop the best treatments for obesity.
"Effects of Diet and Physical Activity Interventions on Weight Loss and Cardiometabolic Risk Factors in Severely Obese Adults - A Randomized Trial"
Bret H. Goodpaster, PhD; James P. DeLany, PhD; Amy D. Otto, PhD; Lewis Kuller, MD; Jerry Vockley, MD, PhD; Jeannette E. South-Paul, MD; Stephen B. Thomas, PhD; Jolene Brown, MD; Kathleen McTigue, MD, MS, MPH; Kazanna C. Hames, MS; Wei Lang, PhD; John M. Jakicic, PhD
JAMA. Published online October 9, 2010. doi:10.1001/jama.2010.1505
Written by Christian Nordqvist