Diet versus Exercise in Obese Older Adults
Monday, April 4, 2011
Regular readers will recall a recent post on the issue of recommending weight loss in older individuals with obesity.
Now Dennis Villareal and colleagues from the Washington University School of Medicine, St. Louis, Missouri, in a paper published in the New England Journal of Medicine, examined the effect of weight loss, exercise, or both on physical function in obese older adults.
In this 1-year, randomized, controlled trial, 107 adults who were 65 years of age or older and obese were randomly assigned to a control group, a weight-management (diet) group, an exercise group, or a weight-management-plus-exercise (diet-exercise) group. A total of 93 participants (87%) completed the study.
The Physical Performance Test score, increased more in the diet-exercise group (21%) than in the diet group (12%) or the exercise group (15%) compared to scores in the control group (1%).
Perhaps surprisingly, the peak oxygen consumption (a measure of fitness) improved more in the diet-exercise group (17%) than in the diet group (10%) or the exercise group (8%).
The Functional Status Score, increased more in the diet-exercise group than in the diet or exercise groups.
Body weight decreased by 10% in the diet group and by 9% in the diet-exercise group, but did not decrease in the exercise group or the control group.
Lean body mass and bone mineral density at the hip decreased less in the diet-exercise group than in the diet group.
Strength, balance, and gait improved consistently in the diet-exercise group.
Adverse events included a small number of exercise-associated musculoskeletal injuries.
The authors conclude that a combination of weight loss and exercise provides greater improvement in physical function than either intervention alone in obese older individuals.
It is perhaps also worth noting that health status and physical functioning improved in all intervention groups compared to doing nothing (controls).
This study certainly lends support to the notion that a combination of diet and exercise may be best to improve both health and physical function in older individuals with excess weight.
AMS
Edmonton, Alberta
Hat Tip to Carla for drawing my attention to this study
Villareal DT, Chode S, Parimi N, Sinacore DR, Hilton T, Armamento-Villareal R, Napoli N, Qualls C, & Shah K (2011). Weight loss, exercise, or both and physical function in obese older adults. The New England journal of medicine, 364 (13), 1218-29 PMID: 21449785
Monday, April 4, 2011
Certainly can’t argue with that conclusion!
With respect to the changes in fitness, it is probably largely due to the way that the data is presented (e.g. relative to body weight, rather than absolute oxygen consumption). The exercise-only group didn’t lose any weight, so their increased score is probably due to increased fitness alone. But when you lose 10kg, as they did in the diet-only group, that’s going to immediately increase your relative VO2max score even if there are no other physiological changes. And since the Diet+Exercise group both lost weight AND exercised, it’s not surprising that they saw the biggest increase. If fitness had been presented in terms of absolute VO2 then I think the numbers would have made a bit more intuitive sense.
I will say that the baseline values, and even those at 1 year, are incredibly low. They’re all in the range of 16-17 ml/kg/min – isn’t 15 ml/kg/min assumed to be the minimum required for independent living? And the fact that the actual increases are in the range of just 1-2 ml/kg/min… is that clinically relevant?
Travis
Monday, April 4, 2011
“The authors conclude that a combination of weight loss and exercise provides greater improvement in physical function than either intervention alone in obese older individuals.”
Indeed, you quote them accurately, and I can argue with it. I don’t know what the “diet” was that was offered, but this is how I’d prefer the wording in their conclusions (projecting my own assumptions on what “diet” was offered):
“. . .a nutritious, mildly restricted diet offered in combination with exercise provides greater improvement in physical function than either intervention alone in obese older individuals. This combination also results in greater average weight losses than exercise alone.”
This would be more accurate. It would ascribe the success to the behavior, not a symptom of the behavior. It would also reduce guilt in those for whom the combination did not produce weight loss but did improve physical function.
Nuance is important.