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Exercise yields similar weight loss whether added simultaneously or sequentially to reduced-calorie diet
Introducing the exercise component of a behavioral weight-loss program 6 months after beginning dietary changes did not make a substantial impact on long-term weight loss compared with incorporating exercise right away, according to findings published in Obesity.
“Many individuals with overweight or obesity are unable to achieve and sustain high levels of exercise with simultaneous delivery of diet and exercise interventions. An alternative approach, which has not been widely considered, is to deliver diet and exercise interventions sequentially,” Victoria A. Catenacci, MD, associate professor of medicine in the division of endocrinology, metabolism and diabetes in the department of medicine at the University of Colorado Anschutz Medical Campus in Aurora, Colorado, and colleagues wrote. “Delaying the start of an exercise intervention after diet-induced weight loss could result in enhanced exercise adherence and improved weight loss long term.”
Catenacci and colleagues analyzed data from 170 adults who participated in a weight-loss program for 18 months. The researchers randomly assigned 85 participants to begin supervised exercise simultaneously with a reduced-calorie diet (mean age, 40 years; 83.5% women; mean BMI, 34.3 kg/m2; ) and 85 participants to postpone exercise onset for the first 6 months (mean age, 39 years; 83.5% women; mean BMI, 34.6 kg/m2). After each group completed 6 months of supervised exercise, they were tasked with maintaining a similar level of activity for the remainder of the program, equating to 300 weekly minutes of activity that required between 65% and 75% of a participant’s maximum heart rate. Calorie restriction plans and group sessions focusing on behavior were included in the program as well. The researchers calculated BMI and assessed waist circumference, fat mass and lean mass for participants at 6-month intervals during the study and compared the data with measures taken at baseline.
Participants who began the exercise program for the first 6 months of the study lost an average of 8.7 kg after 6 months while participants who postponed exercise for the first 6 months lost 6.9 kg (P = .047). However, participants who began the exercise program at the beginning of the study period gained an average of 2.5 kg from months 6 to 18 while those who postponed the exercise program gained 0 kg in the same time period (P = .02). In total, reductions in body weight for the entirety of the 18-month trial were similar between those who began exercise early (6.9 kg) and those who began exercise later (7.9 kg). The researchers also noted that differences in BMI, waist circumference, fat mass and lean mass at 18 months did not reach significance.
The researchers further noted that the participants who began exercising earlier were more adherent to the program, enjoyed exercise more and had more perceived benefits of exercise than those who started later. In addition, the researchers reported that participants who began exercising early experienced 19 adverse events due to exercise while those who began exercising later experienced nine adverse events due to exercise. Despite the numerical gap, “there were no between-group differences in incidence of exercise-related adverse events,” they wrote.
“Benefits of simultaneous initiation of diet and exercise interventions included greater weight loss and improvements in appetitive measures at 6 months as well as enhanced adherence to the 6-month supervised exercise program,” the researchers wrote. “Conversely, benefits of sequential initiation of diet and exercise included continued weight loss during months 6 to 12 and fewer overall exercise-related adverse events. Thus, consideration of these differential benefits, along with individual-specific factors and preferences, may be used to guide the timing of exercise initiation within a behavioral weight-loss program.” – by Phil Neuffer
Disclosures: Catenacci reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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