5 Body Composition Myths You Still Believe

When it comes to body composition, there’s plenty of misinformation. It’s easy to be misled by outdated, contradictory, or entirely incorrect information, and this can lead to stalled progress and unnecessarily extreme diet and exercise habits. 

In this article, we’ll dispel 5 common body composition myths and misconceptions to make sure you have the know-how you need to reach your body comp goals safely and effectively.  

Body composition myth-busting 

From extreme diets to dubious supplement recommendations, the internet is packed full of unscientific advice on how to lose fat and gain muscle. However, alongside these more extreme claims, there’s still plenty of genuine misunderstanding about the basic processes that power body recomposition. The 6 body composition myths below fall into that category – let’s take a look. 

Myth: You can turn fat into muscle

One of the most common body composition myths is that you can turn fat into muscle, or vice versa. Body recomposition is often discussed as though it were a singular process, but it’s actually two distinct processes: fat loss and muscle gain. 

Fact: Fat and muscle are different tissues, and building muscle is a separate process to burning fat 

Fat loss

Losing fat requires a calorie deficit (consuming fewer calories are used through everyday activity and burnt through exercise). A calorie deficit prompts the body to utilise alternative forms of energy, breaking down tissues to fuel key bodily processes.

In a calorie deficit, the body initiates the breakdown of fatty tissues into fatty acids through a process called lipolysis. These fatty acids enter the bloodstream and are further metabolised into additional compounds (such as ketones) which serve as a source of fuel when nutritional intake is low. This process facilitates weight loss through the “burning” of fat for energy. At no point is this fat used to form new tissues such as muscle, even if you’re working out. 

Muscle gain

On the other hand, building muscle requires a calorie surplus (consuming more calories than are used) and progressive challenge to muscles through strength or resistance training. When these conditions are met, muscle hypertrophy (an increase in muscle mass) is possible. 

Of course, it’s a little more complicated than that, with plenty of other factors coming into play. Training type, volume, load, sleep quality, nutrient timing, and protein intake all play a role in successful muscle gain. However, crucially, strength training will not “turn” fat into muscle. Rather, when combined with a caloric surplus and adequate protein intake, strength training will help build new muscle and increase your overall muscle mass. 

Myth: You can spot reduce fat 

Contrary to popular belief, you can’t choose where you burn fat first (or last). The idea of spot reduction of fat appeals to many, and may seem intuitive. After all, for muscle development, if you want big shoulders, you need to work your shoulders. 

Fat loss is not like this, though. Fat is a fuel source for the whole body, and when the body burns fat, this is broken down from where the metabolism wants to break it down, sent to the liver for further processing, and then sent around the body for use as fuel. 

Focused strength training can build muscle in a specific area (for example, the legs), which can add shape and lend you a leaner appearance, but exercise alone will not lead to a reduction in fat in the area.

Fact: You can’t choose where you lose fat first, but you can work towards losing overall body fat

Where we store fat and how this fat is lost during a calorie deficit is largely determined by genetics and hormonal state. For example, people with a higher level of testosterone will tend to store more fat around the midsection, while those with more estrogen will tend to store more fat around the hips and thighs. While all physical activity helps to boost your calorie burn, you won’t necessarily see fat lost from the areas you’re hoping for first. 

As an example, core workouts are a popular method of building core strength. Incorporating core work into your workout routine is a great way to build strength in your abdominals, obliques, pelvic muscles, and lower back, and build a firm foundation for other compound movements. However, these exercises won’t burn fat from your stomach area or automatically lead to six-pack abs if your body fat percentage is higher. This doesn’t mean these exercises aren’t worth incorporating; however, you should aim to be realistic about what they can and can’t do for your body composition. 

Myth: Cardio is the best way to burn fat 

Cardiovascular exercise such as walking, running, swimming, or cycling is a fantastic way to improve cardiovascular health. Cardio helps improve your speed and stamina, reduces your risk of certain chronic conditions, boosts your mood, and has a whole host of other health benefits. However, contrary to common belief, it is not an efficient way to burn fat. 

Fact: A combination of diet, cardio, and strength training is the key to sustainable fat loss 

To understand why cardio alone isn’t the best strategy for fat loss, it’s important to understand why it’s many people’s go-to exercise for weight loss. 

Cardio exercise is a common fat loss strategy because it has a relatively high-calorie burn. For example, if a 155lb adult ran at a 6mph pace (a 10 min mile) for 1 hour, they would burn a total of 704kcal. If that same person did a vigorous weight lifting workout for 1 hour, on the other hand, they would burn a total of 422kcal. From this comparison alone, it would seem that the run is a better weight loss strategy than the strength workout. 

However, what this calculation doesn’t take into account is that both cardio and strength training affect more than pure calorie burn. 

Weight training helps to build muscle mass, which in turn increases metabolic rate, burning more calories over time. Additionally, the metabolic effects of weight training aren’t limited to the time you’re exercising – calorie burn remains higher after your session to aid muscle repair. 

Over time, incorporating strength or resistance training into your workout regime is likely to further your fat loss goals through an increase in lean muscle mass and a boosted metabolic rate. Weight training while in a calorie deficit has the added benefit of sending signals to your metabolism indicating that you need these muscles – this means that any deficit will preferentially be taken from fat, not muscle, helping you to maintain muscle mass as you lose fat.

The second key component to sustainable fat loss is nutrition. Even with a routine of cardio and strength training, if you’re not eating in a calorie deficit, you won’t see fat loss. Working to incorporate a moderate calorie deficit to accompany your increased activity level will help you to see the fat loss you’re after. 

Myth: The greater the calorie deficit, the quicker the fat loss

If a calorie deficit leads to weight loss, then a bigger calorie deficit leads to more weight loss – right? 

Well, not always. 

Fact: Too great of a calorie deficit will not lead to faster fat loss – but it can have negative effects

The size of your calorie deficit will indeed affect your rate of weight – and by extension fat – loss. For someone maintaining a calorie deficit of 200kcal, for example, increasing this deficit to 400kcal would likely lead to them experiencing a faster rate of weight loss. 

However, this isn’t true indefinitely. 

In too large of a calorie deficit, the body may burn other tissues, such as muscle (which is costly for the body to maintain), leading to a loss of lean mass. It may also make “compromises” in other areas, limiting the energy it puts into our immune system or brain function. This can lead to a range of unpleasant symptoms, such as getting sick often, feeling cold, and experiencing brain fog. These are all signs that the body doesn’t have enough energy and that your calorie deficit is likely too big. Research recommends that VLCDs (very low-calorie diets) are only suitable for short periods and under extreme circumstances, and are not recommended for routine weight management. Any VLCD should always be carried out under medical supervision.

Maintaining a moderate calorie deficit of 500kcal per day is likely ideal for fat loss without compromising other tissues. Rather than opting for a more extreme diet, aim to hit a reasonable deficit consistently. This will be more sustainable and more likely to lead to lasting fat loss. 

Myth: To lose fat or gain muscle, I can’t eat x

There are plenty of fat loss “food rules” and detailed nutrition guides for muscle gain out there. However, the idea that there’s only one way to eat and train to lose fat or gain muscle is a misconception. 

Fact: Provided you maintain a calorie deficit (for fat loss) or a calorie surplus (for muscle gain), no food is off-limits 

The good news is that there’s no one way to lose weight or put on muscle. What works for one person may not work for you, and while there are best practices you’ll want to stick to (such as getting adequate protein for muscle gain), a lot of the rest is up to personal preference. 

A 2021 meta-analysis of optimal diet strategies for weight loss compared a range of dietary interventions. The study compared low carbohydrate, high protein, low fat, ketogenic, paleolithic, low-GI, intermittent fasting, Mediterranean, Nordic, vegetarian, DASH (dietary approaches to stop hypertension), and portfolio (low cholesterol vegan) diets. 

The analysis concluded that there was no single best strategy for weight loss and that “the best diet for weight management is one that can be maintained in the long term”.

Because of this, while no food or food group is off-limits, you may want to consider eating foods that will make it easier to stick to your calorie deficit. Highly processed foods will leave you lacking in micronutrients like vitamins and minerals, and leave you feeling hungrier sooner. This can make it difficult to stick to a calorie deficit and impact your progress. Consuming a diet that hits all your macro and micronutrient requirements while incorporating plenty of whole foods, quality protein, and fibre can make it easier to stick to your plan long-term.

This highlights the importance of finding a sustainable nutrition strategy that works for you. A calorie deficit is the only truly necessary factor for weight loss; how you choose to go about that, and the specific foods you do or don’t include in your meal plan, is up to you. For the best chance of success in optimising your nutritional intake for fat loss or muscle gain, we’d recommend speaking to a registered dietician to create a plan that’s customised to your body and goals.  

Ready to hit your body recomposition goals?

Hopefully, this article has busted a few body composition myths. If you’d like to learn more about how to lose fat, gain muscle, maintain a healthy body fat percentage, or reach other body composition goals, we’d recommend heading over to the My Vital Metrics blog, where we’ve covered all these topics and many more. 

Here at My Vital Metrics, we understand that access to accurate data is essential to making long-lasting changes to our health and fitness. If you’re looking to make positive changes to your body composition, then a professional DEXA scan is a great place to start. To find out more or book your first scan, reach out to the team at My Vital Metrics today!