How Rapid Weight Loss Impacts Your Body

As we approach the New Year, you may be focused on your resolutions for 2023. It’s no surprise that these goals often center around weight loss, maybe even rapid weight loss as you fight to see that scale drop quickly. Unfortunately, this approach can lead to yo-yo dieting, lower self-esteem, poor body image, and a preoccupation with food.

With that thought in mind, let’s dive deeper into how rapid weight loss impacts your mind and body.

“Oftentimes, the proponents of rapid weight loss are individuals who have a lot of weight that they should lose,” nutritionist Elaina Efird, RDN, CD, CEDRD, CSSD explains. “So they think that they have to do it as quickly as possible.” In a recent YouTube video, she highlights the body composition analysis results of a female patient who thought just that — but her results weren’t what she expected. 

Before we take a look, it’s important to note that this individual came to The Kahm Clinic purely for weight loss reasons. She had no history of an eating disorder. She had tried fad diets, but none of them produced long-term results. She had also tried programs like Nutrisystem, Jenny Craig, WeightWatchers, and Noom, but again, nothing was successful.

During her first appointment in October, her resting metabolic rate (RMR) was 2,419 calories. To determine her total daily calorie expenditure, we added 360 calories for daily activity and 450 calories for exercise. For exercise, she met with a personal trainer two days a week for strength workouts and then completed cardio workouts two days a week as well. This means that her total daily energy expenditure (TDEE) was 3,229 calories per day. 

From there, we suggested a moderate calorie deficit in order to achieve those weight loss results she wanted. We encouraged her to eat between 2,700 and 2,800 calories each day. “The goal shouldn’t be to eat as little as possible,” Elaina says. “We want you to eat as much as possible while still in that deficit so that you can listen to your hunger and fullness cues, avoid cravings, and have good energy.” This approach will also help to preserve muscle mass and decrease fat mass.

In other words, it’s important that your weight loss efforts are sustainable. 

About three weeks later, she came back in to repeat the body composition analysis test. She told us that she didn’t believe she could eat her recommended calories and still lose weight, so she chose to eat less. How much less? Only 1,600 to 1,700 calories per day. 

Let’s look at her results. At her first visit, she weighed 310.5 pounds, and at her second visit, she weighed 298.7 pounds. However, her muscle mass dropped from 56.3 pounds to 51.0 pounds, and her fat mass dropped from 174.7 pounds to 169.9 pounds. While she lost about 12 pounds of body weight, she lost more muscle mass than fat mass. “When you’re losing weight, you don’t want to lose that much muscle mass compared to fat mass,” Elaina says. “We want to maintain that essential lean mass, especially when exercising to build strength (as this individual was doing).”

These numbers show us that her body was under fueled. Again, we revisited our initial recommendation of 2,700 to 2,800 calories per day. Remember: It’s more maintainable to feed your body as much as possible while still creating a deficit for weight loss.  

This year, instead of focusing on rapid weight loss, try to center your goals around overall health.

Sure, a New Year’s resolution is a great way to highlight what’s important to you and what you want to change. But don’t jump on a program that promises you’ll lose “20 pounds in just three weeks” or make a drastic, unsustainable shift in your diet. If you want to lose weight, adapt healthy lifestyle changes that create positive, long-lasting habits.

Subscribe to our YouTube channel for more video content. To talk to a professional about eating disorder treatment, please reach out to our staff or schedule an appointment at The Kahm Clinic today.