The Metabolism Merry-Go-Round
In society, there is a significant focus on obesity and how high-calorie diets and inactivity contribute to this epidemic in the U.S. But what if we are putting so much emphasis on weight loss, caloric restriction, and “diet culture” that we create yet another metabolic epidemic? While extreme dieting might bring temporary improvements on the scale, there are negative impacts of perpetual dieting and caloric restriction on metabolism.
Metabolism is simply understood as all of the processes happening internally in the human body to make energy. We use this energy for functions such as muscle contractions, nerve signaling, a continuous heartbeat, and other chemical reactions. Our metabolic rate, or the number of calories burnt in a day, is composed of many things. It includes:
Your basal metabolic rate--how many calories you would need if you only laid in bed all day.
Non-exercise activity--walking to the mailbox, getting dressed, making breakfast, doing the laundry, getting in and out of the bath
Exercise activity--purposeful activity such as running, swimming, incline walking, or lifting.
Digesting and processing of food--this sounds crazy, but it requires energy to get all the nutrients out of your food.
An unfortunate result of dieting is that the body doesn’t know the difference between voluntary food restriction and literal famine. To conserve energy, the human body will modify normal processes to be more “fuel-efficient.” The body says, “Hey, I’m not getting enough food, so I can’t keep burning all this energy or I’m going to run out!” The body will use not only fat stores but also muscle mass for an energy source. Without adequate energy intake, there can be a decrease in body temperature, heart rate, blood pressure, and in some cases hair loss and brittle nails. Women may suffer even more considerable damage, including irregularities in menstrual cycles, or they may stop menstruating altogether.
While some of the things listed above are extreme, the body may experience other side effects, including a weight loss plateau, rebound weight gain, increased hunger, and exhaustion. In addition to this, food cravings can lead to periods binges, potentially creating eating disorders and a poor relationship with food.
Does this sound familiar? At first, dieting is awesome because we lose a substantial amount of weight very quickly. However, weight loss will eventually slow down and might even stop. This is our metabolism adapting to caloric restriction. When we see weight loss has stopped, AND we are tired and hungry, we will often revert to eating how we did before dieting. However, when we return to our usual diets, we will likely regain all the weight lost and then some. This is likely due to the decrease in metabolic rate because of the dieting. It’s common to feel discouraged due to the weight gain and at some point, attempt weight loss again with this same strategy. This phenomenon is called “yo-yo dieting.”
Next week, I’ll talk about some practical tips to get off the metabolism merry-go-round and help you find the weight that’s right for you!