Everyone knows that eating a low-fat, low-calorie diet and getting regular exercise helps shed pounds, but a new study led by researchers at Fred Hutchinson Cancer Research Center has found that when it comes to losing weight and body fat, diet and exercise are most effective when done together as compared to either strategy alone.
The results of this randomized trial, led by Anne McTiernan, M.D., Ph.D., director of the Prevention Center and a member of the Hutchinson Center's Public Health Sciences Division, were published online April 14 in Obesity.
The majority of women in the study who both improved their diet and exercised regularly shed an average of nearly 11 percent of their starting weight, which exceeded the study's goal of a 10 percent or more reduction in body weight.
"We were surprised at how successful the women were," McTiernan said. "Even though this degree of weight loss may not bring an obese individual to a normal weight, losing even this modest amount of weight can bring health benefits such as a reduced risk of diabetes, heart disease and cancer."
The year-long intervention involved 439 overweight-to-obese, sedentary, postmenopausal Seattle-area women, ages 50 to 75, who were randomly assigned to one of four groups:
exercise only (goal: 45 minutes of moderate-to-vigorous aerobic exercise per day, five days a week, including three days at the Hutchison Center's exercise facility);
diet only (goal: 1,200 to 2,000 calories a day, depending on starting weight, and fewer than 30 percent of daily calories from fat);
exercise and diet (with the same goals as above); and
"Although numerous studies have examined the effect of lifestyle interventions on weight, few have focused on postmenopausal women, a group that experiences particularly high rates of overweight and obesity," McTiernan said.
At the end of the intervention, the researchers found that the women in the exercise-only group lost, on average, 2.4 percent of their starting weight (with a mean weight loss of 4.4 pounds) as compared to an average weight loss of 8.5 percent among women in the diet-only group (with a mean weight loss of 15.8 pounds). The greatest weight loss was achieved by women who both changed their diet and exercised regularly; these women shed an average of 10.8 percent of their starting weight (with a mean weight loss of 19.8 pounds). Two-thirds of the women in this group achieved the study goal of losing at least 10 percent of their starting weight.
Body-mass index (height-to-weight ratio), waist circumference and percentage of body fat were also significantly reduced among the three intervention groups. The women who were assigned to the nonintervention control group, who did not change their diet or activity level, on average lost less than a pound – a statistically insignificant decrease.
"This study shows that you get the biggest bang for your buck by combining a healthy weight-loss diet – which in this case meant reducing calories by cutting fat intake and boosting the consumption of low-calorie foods – with regular, moderate-intensity aerobic exercise," McTiernan said. "You don't need to be an athlete; walking, biking or gym cardio machines all work well. Start slowly and gradually increase to 45 minutes of activity a day, more if you are able."
In addition to promoting weight loss and preventing weight gain over time, regular exercise helps with balance, strength and fitness. "This helps older people keep active overall, which has been shown to prolong a healthy life," McTiernan said.
The study also found that the women who lost the most weight and body fat kept a food journal, writing down everything they ate and drank with the exception of water and no-calorie drinks. Other strategies associated with the most successful weight loss included preparing meals at home and eating out less often at restaurants. "Doing your own cooking gives you the most control over calories," McTiernan said.
The combined diet-plus-exercise arm of the study followed the current nutrition and physical activity recommendations by the National Institutes of Health Obesity Education Initiative Expert Panel. "Our clinical trial supports these recommendations," McTiernan said.
Despite the overwhelming evidence for the benefits of lifestyle-induced weight loss, there are still major barriers to implementing these programs, the authors wrote. To this end, McTiernan and colleagues are conducting ongoing follow up of these study participants to try to determine factors – both psychological and behavioral – that are associated with long-term weight-loss maintenance. "Identifying factors that help women not only lose weight but keep it off long term will help steer the development and implementation of obesity-treatment programs that have the greatest promise to impact public health," she said.
The National Cancer Institute funded the research, which also involved investigators from the University of Washington School of Medicine, the NCI Office of Cancer Survivorship, the University of British Columbia and Harvard Medical School.
Kristen Woodward | EurekAlert!
New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy