International Mobile-Health Intervention on Physical Activity, Sitting, and Weight: The Stepathlon Cardiovascular Health Study.

BACKGROUND: Although proof-of-concept for mobile health (mHealth) life-style programs targeting physical inactivity and overweight/obesity has been established in randomized trials, the feasibility and effect of a globally distributed, large-scale, mass-participation mHealth implementation has not been investigated. OBJECTIVES: The purpose of this study was to determine the effect of Stepathlon, an international, low-cost, mass-participation mHealth intervention, on physical activity, sitting, and weight. METHODS: We prospectively collected cohort data from participants completing Stepathlon, an annual 100-day global event in 2012, 2013, and 2014. Participants were organized in worksite-based teams, issued pedometers, and encouraged to increase daily steps and physical activity as part of the team-based race. The program was conducted via an interactive multiplatform application available on mobile devices and the Internet. Analysis was performed according to a pre-specified plan. RESULTS: A total of 69,219 subjects participated (481 employers, 1,481 cities, 64 countries, all populated continents, age 36 ± 9 years, 23.9% female, 8.0% high-income countries, and 92.0% lower-middle income countries). After Stepathlon completion, participants recorded improved step count (+3,519 steps/day; 95% confidence interval [CI]: 3,484 to 3,553 steps/day; p < 0.0001), exercise days (+0.89 days; 95% CI: 0.87 to 0.92 days; p < 0.0001), sitting duration (-0.74 h; 95% CI: -0.78 to -0.71 h; p < 0.0001) and weight (-1.45 kg; 95% CI: -1.53 to -1.38 kg; p < 0.0001). Improvements occurred in women and men, in all geographic regions, and in both high and lower-middle income countries, and the results were reproduced in 2012, 2013, and 2014 cohorts. Predictors of weight loss included step increase, sitting duration decrease, and increase in exercise days (all p < 0.0001). CONCLUSIONS: Distributed mHealth implementation of a low-cost life-style intervention is associated with short-term, reproducible, large-scale improvements in physical activity, sitting, and weight. (Effect of the Stepathlon Pedometer Program on Physical Activity, Weight and Well-Being; ACTRN12615001310550).

Low-carbohydrate diets: what are the potential short- and long-term health implications?

Low-carbohydrate diets for weight loss are receiving a lot of attention of late. Reasons for this interest include a plethora of low-carbohydrate diet books, the over-sensationalism of these diets in the media and by celebrities, and the promotion of these diets in fitness centres and health clubs. The re-emergence of low-carbohydrate diets into the spotlight has lead many people in the general public to question whether carbohydrates are inherently 'bad' and should be limited in the diet. Although low-carbohydrate diets were popular in the 1970s they have resurged again yet little scientific fact into the true nature of how these diets work or, more importantly, any potential for serious long-term health risks in adopting this dieting practice appear to have reached the mainstream literature. Evidence abounds that low-carbohydrate diets present no significant advantage over more traditional energy-restricted, nutritionally balanced diets both in terms of weight loss and weight maintenance. Studies examining the efficacy of using low-carbohydrate diets for long-term weight loss are few in number, however few positive benefits exist to promote the adoption of carbohydrate restriction as a realistic, and more importantly, safe means of dieting. While short-term carbohydrate restriction over a period of a week can result in a significant loss of weight (albeit mostly from water and glycogen stores), of serious concern is what potential exists for the following of this type of eating plan for longer periods of months to years. Complications such as heart arrhythmias, cardiac contractile function impairment, sudden death, osteoporosis, kidney damage, increased cancer risk, impairment of physical activity and lipid abnormalities can all be linked to long-term restriction of carbohydrates in the diet. The need to further explore and communicate the untoward side-effects of low-carbohydrate diets should be an important public health message from nutrition professionals.