Diet Plus Exercise Improves Strength in Obese

March 30, 2011-- Regular exercise plus diet may be more effective than either one alone at helping obese older adults improve physical function, a new study shows.

The combination resulted in greater improvements in strength, balance, and gait, compared with diet or exercise alone.

The study is published in the New England Journal of Medicine.

Diet and exercise together “improve physical function and quality of life, and one of the most important goals in this community is to maintain independence,” says study researcher Dennis T. Villareal, MD, chief of geriatrics at the New Mexico VA Healthcare System. Villareal is also a professor of medicine at the University of New Mexico School of Medicine.

Testing Physical Abilities

The study followed 93 obese adults aged 65 and older. Those in the diet plus exercise group saw more gains in a test measuring physical abilities than study participants who were randomly assigned to diet or exercise alone.

Test scores for participants who took part in diet, exercise, or diet plus exercise were greater than scores for those in the comparison group who did not make any changes.

Participants in the diet group were asked to cut back on their daily calories with a goal of losing 10% of their body weight by six months and maintaining that loss for another six months. Those in the exercise group took part in three 90-minute group exercise sessions per week. The sessions included aerobic activity such as walking on a treadmill, indoor cycling, stair climbing, and flexibility and balance exercises.  

Until now, there were more questions than answers about the benefits of diet and exercise in this group.

“Weight loss in this population could be more harmful than beneficial because it can result in loss of muscle mass and worsen physical function,” Villareal says.

Frailty is common in the obese elderly, he says.

“It is the worst of both worlds to be fat and frail because you need muscle to carry your body weight, but you have less muscle mass as you age,” he says.

All obese adults should receive clearance from their doctor before starting an exercise plan, Villareal says. “You need to make sure you don’t have any contraindications to exercise training such as heart disease.”

Exercise did increase the risk of injuries in the new study.

Second Opinion

The new findings mirror what Julie D. Marks, a clinical exercise physiologist at the Lafayette General Medical Center in Lafayette, La., sees in her practice regarding the combined effects of diet and exercise.

“When they do one without the other, we don’t see the results as greatly as when they do both,” she says. “Once they get the weight off, they are brighter and have increased mobility, freedom, strength, and energy.”

Exercise can be done in spurts throughout the day as opposed to one 30-minute session, she says.

Miriam Pappo, RD, director of clinical nutrition at the Montefiore Medical Center in the Bronx, N.Y., says the new findings may not apply to obese older adults who are aged 80 and above.

This age group may have coexisting problems such as age-related cognitive decline or chewing and swallowing problems that may affect their ability to follow a diet.

For those in the age ranges of the new study (65 to 74), Pappo recommends a similar diet to the one in the new study. “I tell them to eat a high-fiber diet with lots of fruits and vegetables, and we will talk about cooking preparation and not skipping meals,” she says.

Pappo always suggests that her older obese patients see a doctor before beginning an exercise regimen.