Brown RE, Sharma AM, Ardern CI, Mirdamadi P, Mirdamadi P, Kuk JL. Secular differences in the association between caloric intake, macronutrient intake, and physical activity with obesity. Obes Res Clin Pract. 2015 Sep 14. pii: S1871-403X(15)00121-0. doi: 10.1016/j.orcp.2015.08.007.
The prevalence of obesity has increased over time and it has been suggested that this is due to the rise in caloric intake and reduced physical activity. However, recent research suggests that there are many factors that can influence body weight and how efficiently we manage calories.
Our study findings suggest that an adult in 2008 will be about 10% heavier in 2008 than an adult of the same age, ethnicity, education level and smoking status in 1971, and about 5% heavier for a given amount of physical activity level in 2006 than 1988. This study used data from a large population of U.S. adults who participated in the National Health and Nutrition Survey (NHANES) between 1971 and 2008.
Though there has been ample research that has shown that eating less and exercising more results in weight loss, these results are largely shown to be ineffective long term. This is because weight management is actually much more complex than just energy in versus energy out. This is akin to saying that 1 gallon of gasoline in any car will result in the same distance travelled regardless of the driving conditions, how well the car is maintained, size of the car or how quickly the driver accelerates or brakes. In the same way, newer research is showing that there are many secular changes in our lifestyle and environment that are changing the way that body weight is controlled such as medication use, environmental pollutants, genetics timing of food intake, stress, gut bacteria and even nighttime light exposure. Together, it suggests that maintaining a healthy body weight is now more challenging than ever as to avoid weight gain, individuals would need to eat even less and exercise more than if they were born 25 years ago..
The Canadian Institutes of Health Research funded study, Secular differences in the association between caloric intake, macronutrient intake, and physical activity with obesity was recently published in Obesity Research & Clinical Practice.