Obesity is a serious problem because the diseases associated with weight gain are expensive to treat and can cause great suffering for the individuals involved. Obesity is not fully understood, but it is accepted that both exercise and nutrition play a part in its development and treatment. Short-term exercise regimens can cause weight loss because they cause a negative energy balance on account of increasing energy expenditure, although the effects of long-term exercise regimens is less well studied. Walking is often recommend as an activity for fighting obesity because it is low impact, inexpensive and can be incorporated easily into daily routing with simple lifestyle changes. The Institute of Medicines current guidelines are that walking 60 minutes per day is enough to prevent obesity, although this assumes no other exercise is performed.
To investigate the long-term effects of walking on the prevention of weight gain, researchers1 studied data collected over 15 years (in the Coronary Artery Risk Development in Young Adults Study; CARDIA). In particular the researchers were interested in the association between the amount of walking an individual performed and the weight gain accumulated in the 15 year study period. The mean baseline weights for the men and women were 77.0 and 63.2 kg, respectively. Over the 15 years there was an increase in body weight and body mass index (BMI; kg/m2), but this was coupled with a decrease in physical activity and a decrease in the amount of walking performed. Women had higher mean walking scores than did men. The researchers found that those subjects who did the most walking had the lowest gain in weight over the 15 years.
Walking might offer effective long-term protection from weight gain and obesity if it is undertaken regularly. In this study, the researcher found that those women with the highest baseline weight gained 13 kg over 15 years if no walking was performed. However, if those women from the same baseline weight performed the most amount of walking (≥ 4 hours per week over 12 months), then the weight gain was only 5 kg. For men with the highest baseline weight, the difference in weight gain between those who did the most walking (≥ 4 hours per week over 12 months) and those who did no walking for those was 4 kg. Therefore, adding 2 to 4 hours per week of walking are easily achievable targets and could help prevent obesity or weight gain over the long-term, especially in women.
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