Effective Weight Control – Caloric Balance Is Key
Weight loss and maintenance of lost weight have been subjects of intense scientific scrutiny for the past 20+ years. The body of evidence confirms that weight losses of at least 10% are more easily achieved than maintaining those weight reductions. Approximately 80% of adults typically regain their lost pounds within a year.
In a recent study, detailed interviews were conducted to identify strategies cited by adults who had successfully maintained body weight losses of at least 30 pounds for more than a year. Thirty-six different habits were identified. A second nationwide survey was then conducted with another group of overweight adults to determine which of the 36 identified practices these men and women found most helpful for accomplishing and maintaining year-long weight losses of at least 10% of initial body weight.
The main conclusion of the study is different approaches are frequently needed for achieving and sustaining meaningful weight losses. Controlling portion size is an effective strategy for both achieving and sustaining weight loss while the value of following an exercise routine provides more benefit for maintaining weight loss. Increased intake of fruits and vegetables is a diet practice that fosters initial and sustained weight loss, whereas the strategy to limit sugar was found to be ineffective for maintaining weight loss.
The major contribution to the scientific literature provided by this study is effective weight-loss strategies are not necessarily those required for preserving weight loss. While a singular focus on reducing caloric intake is beneficial for initial weight loss, maintaining a balance between caloric intake and caloric expenditure is required for successfully sustaining weight loss.
Significance: The balance between caloric intake and caloric expenditure is a more effective strategy to sustain the health benefits of meaningful weight loss than one focused on limiting sugar intake.
Citation: "Practices Associated with Weight Loss Versus Weight-Loss Maintenance: Results of a National Survey." CN Sciamanna, M Kiernan, BJ Rolls, et al. American Journal of Preventive Medicine, August 2011
Exercise – Lifelong Commitment, Lifelong Benefits
Making exercise an integral part of your life goes beyond the visible benefit of weight control. Stopping the nationwide Diabetes Prevention Program clinical trial ahead of schedule confirms the deep-seated value of exercise. Exercise was more effective than medication in reducing the incidence of type-2 diabetes in obese adults with "pre-diabetes" high levels of fasting blood glucose. Exercise was equally beneficial for men and women, for all racial and ethnic groups, and for the younger as well as the older trial participants.
One of the priorities of diabetes research is to decipher the underlying mechanism(s) of how exercise improves blood glucose control. The standard procedure is measurement of insulin sensitivity – the ability of an individual to return the rise in blood glucose level to the pre-test fasting level during a standard glucose tolerance test. Insulin insensitivity means more insulin is required to accomplish this return to the pre-test fasting level.
Directors of a recent study screened the insulin sensitivity of 80 healthy, lean sedentary young males. Study leaders then selected the group of 24-year olds who required the most insulin (insulin insensitive) to return their rise in blood glucose to their pre-test levels. The effect of exercise on the change in insulin sensitivity was measured with this group of young males after they consumed a high-carbohydrate meal.
The main conclusion of the study is: exercise significantly improves insulin sensitivity.
A single bout of vigorous exercise led to a threefold increase in blood glucose utilization in muscle, and a simultaneous 40 percent reduction of triglyceride formation in the liver. The study provides strong evidence that exercise is an effective way to reduce the likelihood of developing fatty liver disease, an acknowledged risk factor for cardiovascular disease and type-2 diabetes.
The major scientific contribution of this study is: Exercise improves blood glucose control even in young healthy individuals.
Redirecting the metabolism of ingested carbohydrates from the liver to muscle reduces the risk of developing the cluster of metabolic disorders that accompany type-2 diabetes. Since individuals having this cluster of metabolic disorders are also more likely to develop heart disease or suffer strokes, exercise provides multiple, longer term health benefits.
Significance: Transforming sedentary behaviors into active lifestyles at a young age bestows life-long health benefits. This study provides added understanding of the long-term health benefits of exercise. Even though the exercise in this study was vigorous, lifelong active lifestyle provides the same benefits.
Citation: "Reversal of muscle insulin resistance with exercise reduces postprandial hepatic de novo lipogenesis in insulin resistant individuals." R Rabøl, KF Petersen, S Dufour, et al. Proceedings of the National Academy of Sciences, August 2011