By Alan Mozes
But the study authors added that exercising in tandem with dieting is probably the best way to go.
The researchers designed the three study interventions so people participating would drop about 7 percent of their body weight -- through any method -- over a roughly three-month period.
The study showed it didn't seem to matter which intervention people chose to lose weight. Participants in all three groups saw their lifetime cardiovascular risk drop from 46 percent to 36 percent.
"Exercise and a low-calorie healthy diet are both known to improve risk factors for cardiovascular disease, even in the absence of weight loss," said study lead author Edward Weiss. He's an associate professor at Saint Louis University's department of nutrition and dietetics, in Missouri.
"In light of this, we expected the combination of diet and exercise to have 'additive effects' on risk factors, and therefore expected greater improvements in the combined-intervention group, as compared to diet or exercise alone," he said.
Instead, the study found that "the magnitude of benefit does not depend on whether diet, exercise, or a combination of diet and exercise is used to promote weight loss," Weiss said.
What really seemed to matter was that people slimmed down.
For the study, investigators divided 52 overweight men and women into one of three groups: a diet group; an exercise group; and a combined diet and exercise group.
Dieters were instructed to cut 20 percent of their caloric intake, while exercisers were told to increase activity levels by 20 percent. The combination group was told to do both by 10 percent.
Weiss described a 20 percent caloric cutback as "modest for most people," equaling a drop of about 300 to 500 calories per day -- roughly the equivalent of two sugary sodas.
But "increasing calorie expenditure by 20 percent per day is more challenging," he said. "Especially for the non-exercising men and women who were recruited for this study. This translates to walking three to five miles, six to seven days per week, for someone who was not exercising when they started the study."
In the end, all three groups registered the same degree of improvement in terms of blood pressure, cholesterol levels and heart rate, and the same amount of heart disease risk reduction, the study findings showed.
But Weiss nevertheless suggested that a combined approach may be best.
The combination group lost weight more quickly and these people were also more likely to stick to their goals, he noted. About 30 percent of study participants from the diet or exercise groups dropped out, but only 5 percent of the combination group quit.
Diet and exercise together may also have "additive benefits for other aspects of health," Weiss said. For example, a bigger cut in type 2 diabetes risk was seen among those who embraced both approaches.
And for reasons not entirely clear, adding exercise to diet appears to specifically confer a cardiovascular advantage, he added.
"If two people have the same blood pressure, cholesterol, family history, age, etcetera, but one person exercises and the other does not, the non-exerciser is two-to-three times more likely to develop heart disease," Weiss said.
Registered dietician Lona Sandon agreed that "both healthy eating and exercise are important given what we know from previous research demonstrating the benefit of each."
Sandon explained that "a healthy diet provides key nutrients for optimal functioning of the body and disease prevention. Exercise cannot provide nutrients, but may help us utilize nutrients more effectively."
And she said that the key to success is choosing pleasure over pain.
"If walking or running on a treadmill seems like punishment, find something else to do. Perhaps weight training, Zumba, or walking in the park is a better option," suggested Sandon. She is an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas.
"Same thing applies to eating," she added. "If drinking kale smoothies seems like punishment, don't bother. Have some carrot sticks dipped in light ranch dressing instead, or keep dessert to just one time per week."
Weiss and his colleagues published their findings online recently in the American Journal of Clinical Nutrition.