The Risks of Gaining or Losing Weight Too Quickly
While many people are interested in losing weight, it can be surprising to hear that there are a number of people who desire weight gain. In fact, the frustrations felt by those attempting to lose weight are equally felt by those who are “hard gainers”, or people who have a difficult time putting on body weight. The fact of the matter is: changing our physique and weight status is challenging!
While it is most important for everyone to focus on healthy behaviors, it is okay to desire a healthy change in body weight. The typical reason for frustrated feelings around weight management tends to do with the timeline – we want immediate results and gratification for our efforts! Unfortunately, pursuing weight loss or weight gain at too rapid of a rate has some dire consequences.
Let’s first look at weight loss.
Losing weight at a rapid rate tends to require some extreme behaviors. Aside from those behaviors typically being unhealthy and unsustainable, they also promote some undesirable outcomes. One of these side effects includes an increased loss of muscle mass relative to loss of fat mass. Typically when someone says they want to lose weight, what they mean is they would like to lose body fat. However, all weight loss is a mixture of muscle and fat loss – there’s no getting around it. Estimates say that around ¼ - ⅓ of weight loss is muscle mass loss. However, some behaviors can promote more or less loss of muscle. For example, engaging in strength training while losing weight can help to preserve some muscle mass during weight loss. On the contrary, losing weight too rapidly will encourage an increased break-down of muscle mass relative to fat mass.
Another consequence of rapid weight loss is a decreased metabolic rate. The majority of the energy a person expends during the day is not through exercise; instead, it is the simple task of keeping the body functioning. This is called the basal metabolic rate (BMR), and it includes the energy required to sustain basic life functions, such as breathing, digesting food, keeping a stable body temperature, and growing skin and hair. For healthy weight management, it is best to keep the basal metabolic rate high, as doing so will mean more calories are burned at rest. This was most popularly observed in the studies that followed The Biggest Loser TV show, where contestants who lost a significant amount of weight in a short period of time had a permanently reduced BMR, increasing their propensity for weight regain.
Lastly, losing weight too quickly can diminish bone density. When stepping on the scale, it is often assumed that increases or decreases in weight are always associated with changes in body fat mass. However, our bones carry weight as well, and their weight can change based on their health. People with less bone density might be lighter on the scale, but their risk of poor health outcomes is greater, including an increased risk of frailty, osteoporosis, and bone fracture. Those weight loss strategies might give the perception of being “healthier” at a younger age, but if they come with the consequence of losing bone density, it will be increasing the risk of poor health outcomes later in life.
Now let’s take a look at the risks of gaining weight too quickly.
When somebody says they would like to gain weight, they typically are intending to gain muscle mass. This muscle mass gain could be for a desired functionality, such as improved athletics, or for aesthetics, such as wanting more curves and definition. For a number of people, gaining weight can actually be quite challenging! This can be difficult for some people to understand – after all, don’t they simply need to eat more food? In reality, the “hard gainers” may feel they are eating food constantly without any results.
One of the major reasons why a person might be a “hard gainer” is due to a factor called NEAT, or Non-Exercise Activity Thermogenesis. This is the energy expended for activities NOT including sleep, digestion or formal exercise. Some people have much higher NEAT expenditure than others. Often these are “fidgety” individuals. They bounce their legs while sitting down; they pace the floor while talking on the phone; they frequently stand up from sitting to stretch their legs; they take breaks to get up during movies. It’s been estimated that individuals with higher NEAT expenditure could burn an additional 300 - 700 calories every day through their fidgety activities! It can be challenging to keep up with the additional food intake needed to just maintain their body weight, let alone gain some.
Just like dieting for weight loss, some people will attempt extreme approaches to gain weight quickly. However, rapid weight gain is often a gain of body fat mass, not increased bone density or muscle mass. Overall, muscle is a healthier metabolic tissue than fat.
Building muscle requires additional calories from nutrient dense foods, including protein, and muscle-building exercises, such as strength training. A reasonable gain in muscle mass per week is about 0.5 - 1 pound. While protein is not the only required nutrient for muscle building, it is an essential building block. Eating a protein rich diet is often very satiating, meaning you will feel full more quickly. Hence, it can be difficult to maintain a calorie surplus while consuming a high protein diet.
As such, those who gain weight rapidly are often consuming nutrient-poor foods, such as sugar-sweetened beverages, fried foods, candy and desserts. These foods will allow a person to achieve a calorie surplus, but they often do not promote muscle growth. Instead, side effects such as brain fog, constipation, sugar crashes, and poor energy ensue. In the long run, poor blood sugar and cholesterol management can also take place. Risks of vitamin and mineral deficiencies are also higher with nutrient-poor diets.
The bottom line is that rapid weight changes are unhealthy, unsustainable, and typically result in undesired consequences. Instead, behavior changes in eating habits and physical activity can promote healthy weight loss or weight gain. Losing 1-2 pounds per week of fat mass and gaining 0.5 - 1 pound per week of muscle mass is a realistic expectation.
Working with a dietitian is the best way to understand why the rate of weight loss or gain matters and how to achieve those changes is a sustainable, healthy way. If you would like to work with me, schedule a FREE discovery call here.