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Weight Loss vs. Fat Loss: Knowing The Difference

It is easy to think that weight loss and fat loss are interchangeable—either way, the end result we are reaching for is a healthy change and an improvement in our wellbeing. The truth is, while fat loss can be a part of losing weight, you usually lose more than just fat.

What does that mean for you and your health goals? For most individuals, fat loss is the goal, so you need to take a deliberate, focused approach for the best results. Read on as we cover the key differences between weight loss and fat loss and how you can optimize for fat loss.

What’s the difference between weight loss and fat loss?

Weight loss is an overall reduction in body weight, while fat loss is a reduction in body fat. When you lose weight, you’re not just losing body fat: you’re making changes to each component of your body composition – body fat, Lean Body Mass, and Body Water. This is true for weight gain as well. You don’t control how much of each you lose, but you can influence what’s lost.

Weight Loss

How does weight loss happen? While there are hundreds of diet and exercise programs out there that will help you achieve fat loss—some better than others—the good ones boil down to essentially the same thing: reducing energy in from food while increasing energy out via exercise/activity (a caloric deficit). This combination forces your body to make up for the missing energy by breaking down your body tissues, including body fat and muscle.

It would be awesome if you could just tell your body to derive all the needed energy from body fat, but that is not what happens. As you lose weight, you will lose some muscle in the form of Lean Body Mass in addition to body fat.

Fat Loss

Body fat, in general terms, is a combination of your essential fat, which plays a vital functional role, and storage fat. Storage fat is adipose tissue that has accumulated as energy reserves. This type of fat will visibly change as you modify your diet and exercise routine. Too much storage fat can negatively impact both our physical and mental wellbeing, so this is what you should focus on for better overall health.

Why you should focus on fat loss and not weight loss?

There is an unfortunate stigma when it comes to weight. While there is a clear link between obesity and chronic diseases, weight loss goals can lead to unintended consequences like disordered eating. That is why a focus on fat loss—and a healthy body composition—is a much better approach because it encourages the individual to move more and eat well.

What are the health benefits of losing fat?

Body fat percentage is a much better gauge of health than weight. Remember that weight is composed of lean body mass, body fat, and water, so any changes in these components can lead to weight gain, not just fat loss.

Excess body fat, especially that storage fat, has a much closer link to chronic diseases like:

  • Type 2 Diabetes

  • Hypertension

  • Heart Disease

  • Various Cancer

Maintaining a healthy body fat percentage can help reduce your risk of these diseases and improve your mental health and overall wellbeing.

What are different ways to measure if you’re losing fat?

To track body fat loss, you’ll need to have your body composition tracked regularly. There are several devices and methods for determining body composition, including calipers, hydrostatic weighing, DEXA, and BIA. If you want truly accurate results, always be tested by a highly skilled professional who uses a medical-grade tool to assess you. $10 plastic calipers and at-home bathroom scales aren’t the best options.

How does your metabolism change with weight loss?

Remember when we said that when you lose weight, you lose more than fat? One of the losses can be from Lean Body Mass, which is critical because the amount of Lean Body Mass that you have directly influences your Basal Metabolic Rate (or what you may refer to as your metabolism). Your Basal Metabolic Rate (BMR) is the number of calories your body naturally burns at rest. When you focus on weight loss and do not make changes to minimize lean body mass loss, you are decreasing the size of your metabolism.

If you maintain the same eating habits, you may be setting yourself up for weight regain.

How weight loss can slow down your metabolism

Here are a typical set of body composition results for someone who would be clinically diagnosed as obese.

Along with high weight and body fat mass measurements, this individual naturally developed muscles by carrying their body weight. What this means is that generally, obese people also have relatively large metabolisms.

An example would be contestants from the reality show, The Biggest Loser. Participants were focused on achieving extreme weight loss over a short period of time. In a study on past Biggest Loser contestants, individuals lost an average of 128.5 pounds in 30 weeks, at a rate of about 4.3 pounds per week.

When the contestants lost all the weight, while they did lose a lot of fat, they also lost a lot of Lean Body Mass—24.5 pounds of it on average—equaling 19% of their total weight loss. This muscle loss contributed to a drop in BMR from 2,607 calories to 1,996 calories. That’s a loss of 600 calories a day—almost an entire meal’s worth of calories, gone!

Dramatic changes to Lean Body Mass and metabolism aren’t ideal, especially when the goal is to maintain healthy body weight. Six years after the end of the competition, the Biggest Loser contestants had regained 83.6% of their fat loss. This was in large part due to the fact that their metabolisms never fully recovered to anything near their original levels. That’s why it is important to come up with a focused approach of gaining muscle and losing fat, or body recompositing, rather than just weight loss.

While the weight and body fat bars are significantly over average, notice that the Skeletal Muscle Mass bar is as well. This is common for an obese person. However, unlike an athlete, an obese person has developed this muscle by virtue of carrying a large amount of weight. Large amounts of muscle develop just to move such a heavy body around. What this means is that generally, obese people also have relatively large metabolisms.

How can I stop my weight regain?

With any weight loss, there will be some Lean Body Mass loss. A low metabolism, coupled with unregulated eating habits, is a surefire way to regain weight back.

Without further development of Lean Body Mass and skeletal muscle to help grow the metabolism, weight regain remains a strong possibility if you aren’t extremely careful with the number of calories you consume. It is crucial to focus on body composition, developing muscle and Lean Body Mass, and changing your eating habits even after you reach your target weight.

How to build muscle, lose fat for a healthy body composition

Here are three main areas to focus on to change your body composition and improve your overall health and wellbeing.

1. Focus on body composition instead of weight loss

Stop tracking weight loss. Instead, track changes in your body composition, which means optimizing your program for fat loss while minimizing Lean Body Mass loss. It’s not like this is impossible, either. Studies have shown that weight loss, when coupled with proper nutrition and strength training, can minimize Lean Body Mass loss.

Body Composition analyzers are a quick, easy way to test regularly and track your progress.

2. Count your calories and develop new eating habits

An important step is to improve your eating habits by choosing an eating plan that you will actually enjoy following and counting your calories.

One thing to keep in mind that optimizing for fat loss will take longer than weight loss. Quick weight-loss plans, like those featured in the Biggest Loser contest, help you lose a lot of weight—almost 4 pounds a week. But you saw what happened: nearly 1/5 of their weight loss was Lean Body Mass, and their metabolisms plummeted.

Effective dietary plans will have you shooting for a ½ – 1 pound of fat loss per week, which is a manageable and sustainable goal that won’t cause such negative effects on metabolism. The slow and steady approach is the better option, and it will lead to long-lasting changes.

3. Start strength training to increase your metabolism

Many people still believe that strength training/weight lifting is only for athletes and bodybuilders. Nothing could be further from the truth. Increased muscle has a whole host of benefits ranging from increased ability to recover from disease, reducing insulin resistance, helping you remain mobile as you age, and, of course, helping to combat obesity by increasing your BMR and metabolism.

Shift to body composition and long-term thinking

As we covered, fat loss is much more important than weight loss and will lead to long-term changes. By working out smarter and finding out what your body composition numbers are, you’ll be on the path to getting fitter while keeping the fat off for good.

Yes, it might take longer than expected, but would you rather drop 30 pounds in less than a year just to regain it all back, or spend the time to make small, impactful changes that lead to a lifetime of good health?

Thank you very much InBody USA for your contribution and publishing of this article. For more visit

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