Many weight-loss programs say you should focus on changing diet first, then exercise, but now new research from Stanford University School of Medicine in the US says for best effects you should do both at the same time.
With colleagues, Abby King, a professor of health research and policy and of medicine, present their findings in a paper to be published this month in the Annals of Behavioral Medicine.
Most people know that the key to keeping weight in check and staying in good health is to eat right and take regular exercise, but millions find it hard to do that, and even to decide which of these to change first.
“It may be particularly useful to start both at the same time,” says King in a press statement, but, she adds:
“If you need to start with one, consider starting with physical activity first.”
King and colleagues looked at published studies on making more than one change to health habits and found conflicting results. Plus, not many have looked at what happens when people try to change more than one health habit at the same time.
So they decided to do their own investigation on the effect of changing diet and exercise together.
Plus, they also wanted to look at one group in particular: those people who say their lives are too busy, that they don’t have enough time to think about how to change diet and exercise. They figured if they could find something that worked for this group, then it would most likely work for others too.
For their study they recruited 200 participants aged 45 and over who were not taking regular exercise and not eating very healthily.
They randomly assigned the participants to one of four telephone coaching groups. One group had telephone sessions with a coach who helped them make changes to diet and exercise at the same time. A second group received telephone coaching that encouraged them to change diet first and not tackle exercise until a few months later, while a third group received coaching that advised the reverse: exercise first, change diet later.
The fourth group acted as controls: they weren’t given any coaching on diet and exercise but on how to manage stress. Success was compared to this group.
All four groups were followed for 12 months..
The US national guideline for a healthy diet is to regularly to be eating five to nine servings of fruit and vegetables a day and ensuring calories from saturated fats are less than 10% of total intake.
The US national guideline for exercise is regularly to be doing at least 150 minutes per week of moderate activity (eg walking for half an hour on 5 days per week).
The results showed that those who started with changes to diet did well in meeting the national guidelines for diet but failed to meet the exercise targets.
The group that started with exercise changes did a good job of meeting both exercise and diet goals, but the most successful group was the one that changed diet and exercise habits at the same time; despite the challenge of making several changes to an already hectic lifestyle.
King says the two changes to lifestyle, diet and exercise, present different challenges for busy people. Changes to diet are probably easier to manage schedule-wise because you don’t have to find extra time, since you have to find time to eat, and you are just substituting one kind of food for another.
But finding time to exercise for 150 minutes a week in an already busy schedule is more of a challenge. Even the most successful group, the one that managed to achieve both the dietary and exercise changes together, struggled with the latter. At first the physical activity goal lagged behind, they attained the dietary one first, but over the course of a year they did eventually manage to reach 150 minutes a week of regular moderate activity.
The style and quality of the coaching is probably a key factor; King says it may help explain the high retention rate of participants in the study.
The coaches met with the participants at the start of the study and then called each of them once a month for a telephone coaching session that lasted no more than 40 minutes, and sometimes only 10 to 15 minutes. The coaches provided advice and support on diet and exercise.
Telephone coaching seems to be a good option for people with a busy lifestyle, says King. It is convenient and flexible, and can provide personalized advice to help individuals whose schedules and pressures make it very hard to change the habits of a lifetime.
“These health behaviors aren’t things that we change over a six-week period and then our job is done,” says King.
“They’re things that people grapple with their whole lives, so to develop ‘touches’ of advice and support in a cost-efficient way is becoming more and more important.”
She also points out that the participants in their study were not actively trying to lose weight, they just wanted to develop healthy habits.
The team now plans to repeat the study with participants who are actively trying to lose weight.
The research was funded by grants from the National Institute on Aging and the National Heart, Lung and Blood Institute.
In another recent study with overweight but otherwise healthy volunteers, researchers from Duke University found that aerobic exercise such as running, walking and swimming is better at eliminating fat than resistance training or using weights.
Written by Catharine Paddock PhD