Exercise alone produces short-term weight loss that is comparable with that induced by diet, after which a plateau in weight loss appears to occur (strength of recommendation [SOR]: B). Exercise in combination with diet promotes maintenance of weight loss above either intervention alone in both obese and overweight men and women (SOR: A). Exercise-induced weight loss has been shown to preferentially reduce abdominal fat and increase lean skeletal muscle compared with that induced by diet (SOR: B)

Cudjoe, Stephanie

Moss, Shannon B.

Nguyen, Loan

University of Missouri: MOspace

 VOL 56, NO 10 / OCTOBER 2007 841www.jfponline.comCLINICAL INQUIRIES From the Family Physicians Inquiries NetworkEvidence-based answerHow do exercise and diet compare for weight loss?The real challenge:Motivating patients to exerciseThe evidence is pretty clear. The real challenge is motivating patients to start and maintain an exercise plan. The key points I make with my patients are: Aim for 5 to 7 times each week. Start slowly (10 minutes per session) and gradually build (at least to 20 minutes within a few months). Walking is often preferred, but do what you enjoy. Having a “buddy” work out with you may help you stick with it. Henry Domke, MDSt. Mary’s Health Center, Jefferson City, Missouri❚ Evidence summaryExercise vs diet: Some conﬂ icting resultsStudies comparing the effectiveness of exercise and diet in weight reduction have yielded confl icting results. Ear-lier studies, including a meta-analysis and randomized (noncontrolled) study, favored interventions that included caloric restriction (diet alone or diet plus exercise).1,2 However, subjects on caloric re-striction regained a signifi cant amount of weight over time (0.9 kg ± 7.7 at 2-year follow-up). Subjects who did aerobic exercise but did not diet lost less weight initially (0.7 kg ± 2.8) but main-tained their weight loss better than those who dieted or dieted with exercise. These earlier studies failed to control for the confounding variable of energy balance—that is, ensuring the amount of calories reduced was comparable with the amount of calories burned through exercise between groups. A more recent randomized controlled trial suggests that aerobic exercise and caloric restric-tion are equally benefi cial in reducing weight for obese men when controlling for negative energy balance.3 However, Exercise alone produces short-term weight loss that is comparable with that induced by diet, after which a plateau in weight loss appears to occur (strength of recommendation [SOR]: B). Exercise in combination with diet promotes maintenance of weight loss above either intervention alone in both obese and overweight men and women (SOR: A). Exercise-induced weight loss has been shown to preferentially reduce abdominal fat and increase lean skeletal muscle compared with that induced by diet (SOR: B). Multiple short bouts of exercise per day are as effective as a single long bout in producing weight loss (SOR: B). Adherence improves when exercise can be completed at home or home equipment is used (SOR: B).Clinical commentaryStephanie Cudjoe, MD and Shannon Moss, PhDBaylor Family Medicine Residency at Garland, Garland, TexasLoan Nguyen, MDBaylor College of Medicine, Houston, TexasFAST TRACKExercise alone is comparable with diet for short-term weight lossCLINICAL INQUIRIES842 VOL 56, NO 10 / OCTOBER 2007  THE JOURNAL OF FAMILY PRACTICEthose who exercised experienced great-er fat reduction and maintenance of skeletal muscle mass than those who only restricted calories. Similar fi ndings regarding fat reduction have been re-ported elsewhere.4 Combining diet and exercise ap-pears to be superior to diet alone, based on the results of a recent meta-analysis of randomized controlled trials.5 How-ever, this meta-analysis did not specify type of exercise, so it is unclear whether outcomes varied by activity.Exercise: Is there a dose-response relationship?Several studies have looked at the rela-tionship between duration and intensity for exercise and weight loss. A dose-response relationship has been observed between the amount of time spent in aer-obic exercise per week and the amount of weight lost for overweight women.6,7 There appears to be no signifi cant difference in weight loss based on dura-tion of a single aerobic exercise episode; rather, weight loss is similar whether completed in short or long bouts.7,8 One study found that at 12 months, individ-uals exercising more than 200 minutes per week lost 7.8 kg more (P<.01) than those exercising less than 150 minutes per week.7 Another study noted that at 18 months, subjects exercising more than 200 minutes per week lost 9.6 kg more than subjects exercising less than 150 minutes per week (P<.05).6Studies with energy expenditure, rather than time spent exercising, as the independent variable had similar results. At 18 months, individuals with higher energy expenditure (2500 kcal/week) lost 6.7 kg ± 8.1 compared with a mean loss of 4.1 ± 8.3 in subjects with lower energy expenditure (maximum of 1000 kcal/week).9 Recommendations from othersThe National Institutes of Health’s Na-tional Heart, Lung and Blood Institute,10 the US Department of Health and Hu-man Services,11 the Centers for Disease How much exercise is best? Government agencies weigh in PHYSICAL AGENCY ACTIVITY LEVEL ACTIVITIES DURATION  FREQUENCY NOTESCDC12 Moderate  Bicycling 5–9 mph, level terrain  30 min 5 or more All adults  or with a few hills, brisk walking,  days/week  golf, mowing lawn, recreational   swimming, scrubbing fl oors/washing   windows, tennis (doubles), weight   lifting/Nautilus machines/free weightsCDC12  Vigorous Bicycling more than 10 mph 20 min 3 or more All adults(alternative)  or on steep uphill terrain, circuit  days/week   training, moving/pushing furniture,  mowing lawn (hand mower),   racewalking, jogging, running,  swimming laps, tennis (singles)DHHS11 Moderate Bicycling (<10 mph), dancing, golf,  60–90 min Daily  All adults attempting  hiking, light gardening/yard work   to lose weight  stretching, walking (3.5 mph),   weight lifting (general light workout)NHLBI10 Moderate Basketball, bicycling 5 miles/30 min, 30 min Daily All adults  gardening, running 10 min/mile,  social dancing, swimming laps,  walking 15–20 min/mileTABLEFAST TRACKExercising at home—or with a “buddy”—should help patients adhere to their regimenControl and Prevention’s Healthy People 201012 recommend between 30 to 90 min-utes of daily moderate physical activity, and that this activity be done at least 5 days a week—or even 7 days per week—depending on whether a person’s goal is weight mainte-nance or weight loss. Another option, offered by the CDC, is that people do 20 minutes of vigorous ac-tivity 3 days or more per week. All of the groups recommend staying within caloric intake requirements (TABLE). ■References  1.  Miller WC, Koceja DM, Hamilton EJ. A meta-analysis of the past 25 years of weight loss research using diet, ex-ercise or diet plus exercise intervention. Int J Obes 1997; 21:941–947.  2.  Skender M, Goodrick G, Del Junco D. Comparison of 2 year weight loss trends in behavioral treatments of obesi-ty: Diet, Exercise, and Combination interventions. J Amer Diet Assoc 1996; 96:342–346.  3.  Ross R, Freeman JA, Janssen I. Exercise alone is an ef-fective strategy for reducing obesity and related comor-bidities. Exerc Sport Sci Rev 2000; 28:165–170. 4.  Tsai A, Sandretto A, Chung Y. Dieting is more effective in reducing weight but exercise is more effective in reducing fat during the early phase of a weight-reducing program in healthy humans. J Nut Biochem 2003; 14:541–549.  5.  Curioni C, Lourenco P. Long-term weight loss after diet and exercise: a systematic review. Internat J Obes 2005; 29:1168–1174.  6.  Jakicic J, Marcus B, Gallagher K, Napolitano M, Lang W. Effect of exercise duration and intensity on weight loss in overweight, sedentary women, a randomized trial. JAMA 2003; 290:1323–1330.  7.  Jakicic J, Winters C. Lang W, Wing R. Effects of intermit-tent exercise and use of home exercise equipment on adherence, weight loss, and fi tness in overweight wom-en—a randomized trial. JAMA 1999; 282:1554–1560.  8.  Schmidt W, Biwer C, Kalscheuer L. Effects of long versus short bout exercise on fi tness and weight loss in over-weight females. J Am Coll Nutr 2001; 20:494–501.  9.  Jeffrey RW, Wing RR, Sherwood NE, Tate DF. Physical activity and weight loss: does prescribing higher physical activity goals improve outcome? Am J Clin Nutr 2003; 78:684–689. 10.  National Institutes of Health, National Heart, Lung, and Blood Institute. Clinical Guidelines on the Identifi cation, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. Obes Res 1998; 6:6–26.  11.  Department of Health and Human Services. Dietary guidelines for Americans 2005 [Internet monograph]. Washington, DC: Department of Health and Human Ser-vices; 2005. Available at: www.health.gov/dietaryguide-lines/dga2005/document/html/chapter4.htm. Accessed on September 4, 2007. 12.  Healthy People 2010 [Web site]. Rockville, Md: Offi ce of Disease Prevention and Health Promotion, US Depart-ment of Health and Human Services; 2002. Available at: www.healthypeople.gov/document/html/volume2/22physical.htm. Accessed on September 4, 2007.CLINICAL INQUIRIES844_JFP1007 844 9/17/07 3:07:01 PM

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