Weight loss, health and fitness are often lumped into the same category. But while it is true that obesity tends to contribute to heart disease, diabetes and other serious conditions, losing weight alone will not necessarily make you healthier or fitter. In fact, if you lose weight by dieting alone, you may be predisposing yourself to other unhealthy conditions.
Weight Loss vs. Fat Loss
Severely restricting your calories or going on an extreme low-carb diet will cause you to lose weight, even if you never exercise. But before you starve yourself, consider whether you want to just lose pounds or if you want to lose pounds of fat. One reason crash diets result in rapid weight loss is that you lose muscle, and muscle contains water, which weighs heavy on the scale. On the other hand, adding exercise to your weight loss regimen will improve your cardiovascular health, reduce the risk of diabetes and preserve metabolism-boosting bone and muscle while still rendering a desirable drop in weight.
Muscle Loss and Metabolism
In a 2009 study reported in "Medical Science of Sports Exercise," researchers compared the effects of weight loss in 30 senior citizens, half of whom lost weight by diet alone and half of whom engaged in diet plus exercise. The researchers concluded, "Exercise added to diet reduces muscle mass loss during voluntary weight loss and increases muscle strength in frail obese older adults." Because muscle is metabolically active tissue, it contributes to basal metabolic rate, or BMR, which is the amount of energy required for basic daily metabolism. An elevated BMR means a higher daily caloric expenditure. Losing muscle lowers your BMR, making it harder to lose weight and to maintain weight loss.
Dieting and Bone Density
Another study published in 2006 in the "Archives of Internal Medicine" observed the effects of diet and exercise on bone mineral density, or BMD. In this study, 48 adults with an average age of 57 were divided in two groups. One group lost weight by caloric restriction alone, while the other group included exercise to their weight loss regimen. While both groups lost weight, the exercise group maintained a higher BMD. Researchers concluded that calorie restricted weight loss that does not include exercise "is associated with reduction in BMD at clinically important sites of fracture."
Maintaining Weight Loss
While weight management is an important part of staying healthy, total fitness and wellness require lifestyle behaviors that include exercise, balanced nutrition and abstaining from unhealthy behaviors such as smoking. A calorie-restricted weight loss plan may lower the number on the scale, but in reality, no one knows how much you weigh. A fit, muscular body, on the other hand, will make you look thinner and healthier and help your clothes fit better. When it comes to maintaining weight loss, a healthy lean muscle mass will keep your engine revving all day long, and exercise will help burn away extra calories.
References
- IDEA Health and Fitness Association: Bone Mineral Density and Weight Loss; Diane Lofshult, May 2007
- Medical Science of Sports Exercise: Exercise Attenuates the Weight-Loss Reduction in Muscle Mass in Frail Obese Older Adults; Tiffany N. Frimal, et. al., July 2008
- American College of Sports Medicine: Physical Activity and Public Health Guideline
Member Comments