From the Desk of Joleen Wilson, Pathway Dietician: Metabolism is King
Written by: Joleen Wilson, Registered Dietician, Certified Nutrition Support Clinician, for Pathway for Eating Disorders Treatment at Brookhaven Hospital
Many people start a diet with the idea that losing a few pounds will motivate them to healthier habits. However, because of a series of body responses to restriction, they actually tend to regain all the weight they lost and, in most cases, a few pounds more. I am going to try to break this down as simply as possible, because it pertains to everyone. Your metabolic rate (metabolism) is the single and only factor that determines fat loss, not caloric deficit and not doing endless hours of cardio. You could eliminate carbs or fat and finish each day in a 500 calorie deficit, but with no or low metabolic rate, you cannot and will not lose body fat.
Initial weight loss when dieting is the direct result of diuresis. The body raids glucose stores (glycogen), taking out 4 grams of water for every gram of glycogen. If diets are cyclic (repeated loss and regain), glycogen, water, and adipose (fat) are regained, plus five pounds more. Often, muscle tissue is not recovered if the individual does not strength train. The result is less metabolically active tissue (muscle) and more storage tissue (adipose), therefore decreasing metabolism over time. As a result, each subsequent attempt at dieting becomes more difficult.
Many people with restricting behavior fall into a cycle of restriction followed by bingeing and subsequent weight gain. With restriction of food intake, muscle and essential organ tissue is often eroded and burned for energy. The body will eventually decrease the person’s energy level and the metabolism decreases by as much as 40%.
The majority of individuals who are chronic dieters are not very successful in the long-term. The science of the their metabolic rate is working against them. In order to get ready for a vacation, a wedding or what have you, people will follow these strict, low calorie plans that include endless cardio. They damage their metabolic rate so much that their basal metabolic rate (BMR, the calories burned if you laid still all day and did not move) may be as low as 200-300 calories per day. A normal, healthy female’s BMR is about 1500 calories. So the minute the event is over and they eat a few normal meals, while not doing the double cardio sessions, the body immediately and quickly gains body fat. A healthy person would have their metabolism to keep them in check.
Next time I will talk about specific things that damage metabolic rate as well as those that support it.