Does all Weight Loss = Fat Loss?

Beyond the Scale: Why Weight Loss Isn't Always What It Seems

Disclaimer: This blog post includes references to scientific studies. The numbers in brackets refer to the numbered items in the reference list at the end of the post.

The scale is down, you're feeling lighter, and you're celebrating your weight loss. But is that weight loss entirely fat loss? It's a question many people ask, and the answer might surprise you. Let's delve into the nuances of weight loss and understand why it's not always synonymous with fat loss.

Understanding Weight Loss vs. Fat Loss:

• Weight Loss:

  • This is a decrease in your overall body mass/weight.

  • It can encompass a reduction in fat, muscle, water, and even bone mass.

  • The scale simply reflects the total weight change, not the composition of that change.

• Fat Loss:

  • This specifically refers to a reduction in body fat.

  • It's the type of weight loss that improves body composition, reduces health risks, and enhances physical appearance.

  • Fat loss is the desired outcome for most people aiming for long-term health and fitness.

We live in a world obsessed with weight loss. Everywhere you look, there are ads for diets, workout programs, and weight loss supplements, all promising quick and easy ways to shed those pounds. But what if I told you that the number on the scale doesn't always tell the whole story? What if that weight loss you're celebrating is actually doing more harm than good?

It's a scary thought, but it's true. The truth is that weight loss is a complex process, and focusing solely on the number on the scale can be misleading. You could be losing weight, but you might be losing muscle mass instead of fat. And that's a big problem.

Sarcopenia (loss of muslce mass and strength)(1), which is age-related muscle loss, can begin as early as our 30s and it accelerates as we get older. We can/may lose 3% to 5% of our total muscle mass (~ 1.8kg to 2.7kg of muscle)(1). Why does this matter you may ask? Well, as we age, we naturally begin to lose muscle mass. However, sarcopenia can significantly impact our quality of life, leading to decreased mobility, increased risk of falls and fractures, and a greater risk of developing chronic diseases(2).

Maintaining muscle mass is crucial for everyone, but it becomes even more critical as we age to offset the effects of sarcopenia.

The Importance of Body Composition

So, what should you focus on instead? The answer is body composition. Body composition is the proportion of fat and muscle in your body. A healthy body composition is one with a high proportion of muscle and a low proportion of fat [2].

This is why exercise is so important. Studies have shown that exercise, especially when combined with a ‘healthy diet‘, can help you lose fat and gain muscle [3, 4]. This means that even if the number on the scale doesn't change much, you could be making significant improvements in your health [3, 4].

How Exercise Helps

One study published in PubMed found that regular exercise, even without weight loss, can significantly reduce total and visceral fat and increase skeletal muscle mass in obese individuals, including those with type 2 diabetes [4]. Another study in PMC indicates that exercise training leads to favourable changes in body composition, such as decreased fat mass and increased muscle mass, and is more effective for maintaining weight loss than achieving large amounts of weight loss initially [3].

The Dangers of Weight Loss Without Exercise

On the other hand, losing weight without exercise, especially through restrictive dieting, can lead to muscle loss [2]. This is because when you don't eat enough calories, your body starts breaking down muscle for energy [2]. This is why many people who lose weight through dieting alone often regain it all back, and sometimes even more. They've lost muscle, which has slowed down their metabolism, making it harder to burn calories [2].

The Bottom Line

The bottom line is that weight loss is not always a good indicator of improved health. It's much more important to focus on body composition. By combining a ‘healthy diet‘ with regular exercise, you can lose fat, gain muscle, and improve your overall health, regardless of what the scale says. So, step away from the scale and focus on what really matters: becoming a healthier, stronger you.

Bonus Facts Why Weight Loss Isn't Always Fat Loss:

1. Water Weight:

   • Fluctuations in water retention can significantly impact your weight.

   • Factors like sodium intake, hormonal changes, and carbohydrate consumption can affect water weight [2].

   • Initial weight loss on a new diet is often due to water loss, not fat loss [2].

2. Muscle Loss:

   • Restrictive diets and inadequate protein intake can lead to muscle loss [2].

   • Muscle is metabolically active, meaning it burns calories at rest. Losing muscle can slow your metabolism and hinder long-term fat loss [2].

   • Cardio without strength training can also lead to muscle loss [3, 4].

3. Glycogen Depletion:

   • Glycogen is stored carbohydrates in your muscles and liver. When you restrict carbohydrates, your body depletes glycogen stores, leading to weight loss [3, 4].

   • This weight loss is primarily water, as glycogen holds onto water [3, 4].

4. Dehydration:

   • Dehydration will lower your weight, but is not fat loss, and is very unhealthy [2].

References:

1. Harward Health. Age and muscle loss [Internet]. Harvard Health. 2021. Available from: https://www.health.harvard.edu/exercise-and-fitness/age-and-muscle-loss

2. Hall KD, Kahan S. Maintenance of lost weight and long-term management of obesity. Medical Clinics of North America. 2018;102(1):183–97.

3. Bellicha A, Baak MA, Battista F, Beaulieu K, Blundell JE, Busetto L, et al. Effect of exercise training on weight loss, body composition changes, and weight maintenance in adults with overweight or obesity: An overview of 12 systematic reviews and 149 studies. Obesity Reviews [Internet]. 2021 May 6;22(S4). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8365736/

4. Lee S, Kuk JL, Davidson LE, Hudson R, Kilpatrick K, Graham TE, et al. Exercise without weight loss is an effective strategy for obesity reduction in obese individuals with and without Type 2 diabetes. Journal of Applied Physiology. 2005 Sep;99(3):1220–5.

5. Meerman R, Brown AJ. When somebody loses weight, where does the fat go? BMJ [Internet]. 2014 Dec 16;349(dec16 13):g7257–7. Available from: https://www.bmj.com/content/349/bmj.g7257

6. Freire R. Scientific evidence of diets for weight loss: different macronutrient composition, intermittent fasting and popular diets. Nutrition. 2019 Jul;69(110549).